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THE   UNIVERSITY   OF   CALIFORNIA         LIBRARY   OF   THE    UNIVERSITY   OF 


MANUAL 


LIBRARV 

COLLEGE  OF 

AGRICULTURE 

Berkeley.  Cal. 


OF 


CONTAINING 

The  Elements  of  the  Science  of  Minerals  and  Ms. 

FOB  THE  USE  OF 

THE  PRACTICAL  MINERALOGIST  AND  GEOLOGIST  AND  FOR  INSTRUCTION 
IN  SCHOOLS  AND  COLLEGES. 


BY  JAMES  D.  DANA. 


\\ 


FOURTH    EDITION. 

REVISED  THROUGHOUT  AND  ENLARGED. 

ILLUSTRA  TED  BY  NUMEROUS  WOOD-CUTS. 


NEW  YORK: 
JOHN    WILEY    &   SONS. 

1887. 


EARTH' 

SCIENCES 

LIBRARY 


Copyright,  1887. 
By  JOHN  WILEY  &  SONS. 


PREFACE. 


SCIENCES 

LIBRARY 


THE  preface  to  the  third  edition  of  this  work  (1878)  is  as  follows: 

"This  Manual  in  its  present  shape  is  new  throughout.  In  the 
renovation  it  has  undergone,  new  illustrations  have  been  introduced, 
an  improved  arrangement  of  the  species  has  been  adopted,  the  table 
for  the  determination  of  minerals  has  been  reconstructed,  and  the 
chapter  on  Rocks  has  been  expanded  to  a  length  and  fulness  that 
renders  it  a  prominent  part  of  the  work.  But  while  modified  greatly 
in  all  its  parts,  it  is  still  simple  in  its  methods  of  presenting  the  facts 
in  crystallography,  and  in  all  other  explanations  ;  and  special  prom- 
inence is  given,  as  in  former  editions,  to  the  more  common  minerals, 
with  only  a  brief  mention  of  others.  The  old  practical  feature  is 
retained  of  placing  the  ores  under  the  prominent  metal  they  contain, 
and  of  giving  in  connection  some  information  as  to  mines  and  mining 
industry. 

"  The  student  is  referred  to  the  Text-book  of  Mineralogy,  prepared 
mainly  by  Mr.  E.  S.  DANA,  for  a  detailed  exposition  of  the  subject  of 
crystallography  after  Naumann's  and  Miller's  systems,  and  also  of 
optical  mineralogy  and  other  physical  branches  of  the  science;  to  the 
Manual  of  Determinative  Mineralogy  and  Blowpipe  Analysis  by 
Professor  GEORGE  J.  BRUSH,  for  a  thorough  work  on  the  use  of  the 
blowpipe,  and  complete-  tables  for  the  determination  of  minerals;  and 
to  the  author's  Descriptive  Mineralogy  and  its  Appendixes  for  a  com- 
prehensive treatise  on  minerals." 

In  this,  the  fourth,  edition  the  general  plan  and  scope  of  the  work 
remain  unchanged.  But  it  has  been  revised  throughout,  and  brought 
down  to  the  year  1886  in  its  descriptions  of  minerals,  and  in  the  in- 
troduction of  the  many  new  species  announced  during  the  past  eight 
years.  The  chapter  on  Rocks  has  been  rewritten,  rearranged,  much 
enlarged,  and  supplied  with  new  illustrations.  The  work  is  greatly 
indebted,  for  facts  about  ores  and  other  useful  minerals,  to  the  excel- 
lent annual  report  on  the  "Mineral  Resources  of  the  United  States," 
by  Mr.  Albert  Williams,  Jr.  ,  published  by  the  United  States  Geologi- 
cal Survey.  The  author  would  acknowledge  also  his  obligations  to 
Prof.  B.  J.  Harrington,  of  Montreal,  for  the  revision  of  the  list  of 
localities  in  Ontario  and  Quebec. 

JAMES  D.  DANA. 

NEW  HAVEN,  Dec.  15,  1886. 


TABLE  OF  CONTENTS. 


MINERALOGY. 

PAGE 

MINEBALS  :  General  Remarks 1 

I.  CRYSTALLIZATION   OP   MINERALS:    CRYSTALLOG- 
RAPHY. 

1.  General  Remarks  on  Crystallization 4 

2.  Descriptions  of  Crystals 8 

Explanation  of  Terms 8 

Measurement  of  Angles ;  Goniometers 9 

1.  SYSTEMS  OF  CRYSTALLIZATION  :  Forms  and  Struc- 

ture of  Crystals 15 

1.  Isometric  System 18 

2.  Tetragonal  System 31 

3.  Orthorhombic  System 38 

4.  Monoclinic  System 41 

5.  Triclinic  System 45 

6.  Hexagonal  System. 47 

A.  Hexagonal  Section 47 

B.  Rhombohedral  Section 51 

7.  Distinguishing  Characters  of  the  Systems 56 

2.  TWIN  OR  COMPOUND  CRYSTALS 57 

3.  PARAMORPHS  ;  PARAMORPHISM 61 

4.  PSEUDOMORPHS  ;  PSEUDOMORPHISM 61 

5.  CRYSTALLINE  AGGREGATES 63 

H.  PHYSICAL  PROPERTIES  OF  MINERALS. 

1.  Hardness 67 

2.  Tenacity 67 


Vi  TABLE   OF  CONTENTS. 

PAGE 

3.  Specific  Gravity 68 

4.  Kef raction  and  Polarization 70 

5.  Diaphaneity,  Lustre,  Color 80 

6.  Electricity  and  Magnetism 84 

7.  Taste,  Odor 85 

in.  CHEMICAL  PROPERTIES  OP  MINERALS. 

1.  Chemical  Composition 86 

2.  Chemical  Reactions 92 

A.  Trials  in  the  Wet  Way 92 

B.  Trials  with  the  Blowpipe 93 

IV.  DESCRIPTIONS  OP  MINERALS. 

1.  Classification 103 

2.  General  Remarks  on  Ores 104 

I.  MINERALS  CONSISTING  OF  THE  ACIDIC  ELEMENTS. 

1.  Sulphur  Group 106 

2.  Boron  Group 109 

3.  Arsenic  Group 110 

4.  Carbon  Group 115 

II.  MINERALS   CONSISTING   OF    THE    BASIC   ELEMENTS 

WITH     OR    WITHOUT    ACIDIC — THE    SILICATES    EX- 
CLUDED. 

Gold 122 

Silver  and  its  Compounds 129 

Platinum,  Iridium,  Ruthenium 139 

Palladium 141 

Mercury  and  its  Compounds 142 

Copper  and  its  Compounds 145 

Lead  and  its  Compounds 160 

Zinc  and  its  Compounds 170 

Cadmium,  Tin 175 

Compounds  of  Titanium 178 

Cobalt  and  Nickel  and  their  Compounds 180 

Uranium  and  its  Compounds 186 

Iron  and  its  Compounds 188 

Manganese  and  its  Compounds 206 


TABLE  OF  CONTENTS.  yii 

PAGE 

Compounds  of  Aluminium 211 

Compounds  of  Cerium,  Yttrium,  Erbium,  Lanthanum,  and 

Didymium 221 

Compounds  of  Magnesium 223 

Compounds  of  Calcium 227 

-    Compounds  of  Barium  and  Strontium 240 

Compounds  of  Potassium  and  Sodium 243 

Compounds  of  Ammonium 249 

Compounds  of  Hydrogen 251 

III.  SILICA  AND  SILICATES. 

l.  SILICA. 

Quartz 253 

Opal 259 

2.  SILICATES. 
General  Remarks.- 262 

1.  Anhydrous  Silicates. 

1.  Bisilicates 263 

Pyroxene  and  Amphibole  Group 265 

Beryl,  etc 274 

2.  Unisilicates 275 

Chrysolite  Group 277 

Garnet  Group 278 

Zircon  Group 281 

Vesuvianite,  Epidote,  etc 282 

Axinite 286 

Danburite,  lolite 286 

Mica  Group 287 

Scapolite  Group 292 

Nephelite,  Sodalite,  Leucite 293 

Feldspar  Group 296 

8.  Subsilicates 302 

Chondrodite 303 

Tourmaline 304 

Andalusite,  Fibrolite,  Cyanite 306 

Topaz,  Euclase .^7rT. 309 

Datolite,  Sphene 311 

Staurolite. . .  .  313 


Vlll  TABLE   OF  CONTENTS. 

2.  Hydrous  Silicates. 

PAGE 

1.  General  Section 315 

Pectolite,  Laumontite,  Apophyllite 315 

Prehnite,  Allophane 317 

2.  Zeolite  Section 319 

Thomsonite,  Natrolite 320 

Analcite,  Chabazite 322 

Harmotome,  Stilbite 323 

Heulandite 325 

8.  Margarophyllite  Section 326 

Talc,  Pyrophyllite,  Sepiolite   326 

Glauconite 329 

Serpentine,  Deweylite,  Saponite 329 

Kaolinite,  Pinite 332 

Hydromica  Group 335 

Fahlunite 336 

Chlorite  Group 337 

IV.  HYDROCARBON  COMPOUNDS. 

1.  Simple  Hydrocarbons 842 

2.  Oxygenated  Hydrocarbons 348 

3.  Asphaltum,  Mineral  Coals 349 

SUPPLEMENT  TO  DESCRIPTIONS  OF  SPECIES. 
Catalogue  of  American  Localities  of  Minerals 858 

V.  DETERMINATION  OP  MINERALS. 

General  Remarks 405 

Synopsis  of  the  Arrangement 410 

Table  for  the  Determination  of  Minerals 413 


ON  ROCKS. 

1.  Constituents  of  Rocks 434 

2.  Distinctions  among  Rocks 436 

8.  The  Investigation  of  Rocka 447 


TABLE   OF   CONTENTS.  IX 

PAGK 

4.  Microscopic  Characteristics  of  Rock  Constituents 454 

5.  Descriptions  of  Rocks 457 

I.  Calcareous  Rocks  or  Limestones 457 

II.  Fragmented  Rocks,  exclusive  of  Limestones 461 

III.  Crystalline  Rocks,  exclusive  of  Limestones 466 

A.  Siliceous  Rocks,  consisting  mainly  of  Silica 468 

B.  Containing  Feldspar,  Mica,  Leucite,   Nephelite, 

Sodalite,    or   other   related   Alkali-bearing 
species 469 

a.  Potash-Feldspar  and  Mica  Series 469 

b.  Potash -Feldspar  and  Hornblende  or  Pyroxene 

Series 477 

c.  Potash-Feldspar  and  Nephelite  Series,  Horn- 

blendic  or  not 478 

d.  Leucite  Rocks,  with  or  without  Augite 479 

e.  Soda-Lime-Feldspar  and  Mica  Series 480 

/.  Soda-Lime-Feldspar  and  Hornblende  or  Pyrox- 
ene Rocks 480 

C.  Saussurite  Rocks 487 

D.  Rocks  without  Feldspar 487 

1.  Garnet,  Epidote,  and  Tourmaline  Rocks 487 

2.  Hornblende,  Pyroxene,  and  Chrysolite  Rocks.  488 

E.  Hydrous  Magnesian  and  Aluminous  Rocks 489 

6.  Durability  in  Rocks 491 


ACADEMY  COLLECTION  OF  MINERALS 495 

INDEX..  ,.  497 


MINERALOGY. 


MINERALS. 

MINERALS  are  the  materials  of  which  the  earth  consists, 
and  plants  and  animals  the  living  beings  over  the  surface 
of  the  mineral-made  globe.  A  few  rocks,  like  limestone 
and  quartzite,  consist  of  a  single  mineral  in  more  or  less 
pure  state;  but  the  most  of  them  are"  mixtures  of  two  or 
more  minerals.  Through  rocks  of  each  kind  various  other 
minerals  are  often  distributed,  either  in  a  scattered  way,  or 
in  veins  and  cavities.  Gems  are  the  minerals  of  jewelry; 
and  ores,  those  that  are  important  for  the  metal  they  con- 
tain. Water  is  a  mineral,  but  generally  in  an  impure  state 
from  the  presence  of  other  minerals  in  solution.  The  at- 
mosphere, and  all  gaseous  materials  set  free  in  volcanic  and 
other  regions,  are  mineral  in  nature,  although,  because  of 
their  invisibility,  seldom  to  be  found  among  the  specimens 
of  mineral  cabinets.  Even  fossils  are  mineral  in  composi- 
tion. This  is  true  of  coal  which  has  come  from  buried 
plant-beds,  and  amber  from  the  buried  resin  of  ancient 
trees,  as  well  as  of  fossil  shells  and  corals. 

It  is  sometimes  said  that  minerals  belong  to  the  mineral 
kingdom,  as  plants  to  the  vegetable  kingdom,  and  animals 
to  the  animal  kingdom.  Substituting  the  term  inorganic 
for  mineral,  the  statement  is  right;  for,  as  there  are  the 
two  kingdoms  of  life,  so  there  is  in  Nature  what  may  be 
called  a  kingdom,  or  grand  division,  including  all  species 
not  made  through  the  organizing  principle  of  life.  But 
this  inorganic  kingdom  is  not  restricted  to  minerals;  it 
embraces  all  species  made  by  inorganic  forces;  those  of  the 
earth's  crust  or  surface,  and,  also,  whatever  may  form  un- 
der the  manipulations  of  the  chemist.  The  laws  of  com- 
position and  structure,  exemplified  in  the  constitution  of 
rocks,  are  those  also  of  the  laboratory.  A  species  made  by 
1 


CH^  RACl'ERS  'OF   MINERALS. 


art,  as  we'  term  it,  is  not  a  product  of  art,  but  a  result 
solely  of  the  fundamental  laws  of  composition  which  are  at 
the  basis  of  all  material  existence;  and  the  chemist  only 
supplies  the  favorable  conditions  for  the  action  of  those 
laws.  Mineral  species  are,  then,  but  a  very  small  part  of 
those  which  make  up  the  inorganic  kingdom  or  division  of 
Nature. 

CHAEACTEES  OF  MINEEALS. 

1.  Minerals,  unlike  most  rocks,  have  a  definite  chemical 
composition.     This  composition,  as  determined  by  chemi- 
cal analysis,  serves  to  define  and  distinguish  the  species, 
and  indicates  their  profoundest  relations.     Owing  to  differ- 
ence   in    composition,  minerals   exhibit  great  differences 
when  heated,  and  when  subjected  to  various  chemical  rea- 
gents, and  these  peculiarities  are  a  means  of  determining 
the  kind  of  mineral  under  examination  in  any  case.     The 
department  of  the  science  treating  of  the  composition  of 
minerals  and  their  chemical  reactions  is  termed  CHEMICAL 
MINERALOGY. 

2.  Each  mineral,  with  few  exceptions,  has  its  definite 
form,  by  which,  when  in  good  specimens,  it  may  be  known, 
and  as  truly  so  as  a  dog  or  cat.     These  forms  are  cubes, 
prisms,  double  pyramids,  and  the  like.     They  are  included 
under  plane  surfaces  arranged  in  symmetrical  order,  ac- 
cording to  mathematical  law.     These  forms,  in  the  mineral 
kingdom,  are  called  crystals.     Besides  forms,  there  is  also, 
as  in  living  individuals,  a  distinctive  internal  structure  for 
each  species.     The  facts  of  this  branch  of  the  science  come 
under  the  head  of  CRYSTALLOGRAPHIC  MINERALOGY. 

3.  Minerals  differ  in  hardness — from  the  diamond  at  one 
end  of  the  scale  to  soapstone  at  the  other.     There  is  a  still 
lower  limit  in  liquids  and  gases;  but  of  the  hardness  or  co- 
hesion in  this  part  of  the  series  the  mineralogist  has  little 
occasion  to  take  note. 

Minerals  differ  in  specific  gravity,  and  this  character, 
like  hardness,  is  a  most  important  means  of  distinguishing 
species. 

Minerals  differ  in  color,  transparency,  lustre,  and  other 
optical  characters. 

A  few  minerals  have  taste  and  odor,  and  when  so  these 
characters  are  noticed  in  descriptions. 


CHARACTERS   OF   MINERALS.  3 

The  facts  and  principles  relating  to  the  above  characters 
are  embraced  in  the  department  of  PHYSICAL  MINER- 
ALOGY. 

In  addition  to  the  above-mentioned  branches  of  the  sci- 
ence of  minerals  there  is  also  (4)  that  of  DESCRIPTIVE 
MINERALOGY,  under  which  are  included  descriptions  of 
the  mineral  species;  and  (5)  that  of  DETERMINATIVE  MIN- 
ERALOGY, which  gives  a  systematic  review  of  the  methods 
for  determining  or  distinguishing  minerals. 

These  different  branches  of  the  subject  are  here  taken  up 
in  the  following  order:  I.  Crystallographic  Mineralogy; 
II.  Physical  Mineralogy;  III.  Chemical  Mineralogy;  IV. 
Descriptive  Mineralogy;  V.  Determinative  Mineralogy. 
On  account  of  the  brief  manner  in  which  the  subjects  are 
treated  in  this  volume,  the  heads  used  for  the  several  parts 
are,  (1)  The  Crystallization  of  Minerals;  (2)  Physical 
Properties  of  Minerals  ;  (3)  Chemical  Properties  of  Miner- 
als; (4)  Descriptions  of  Species;  (5)  Determination  of 
Minerals. 


CRYSTALLOGRAPHY. 


I.  CRYSTALLIZATION  OF  MINERALS:  CRYSTAL- 
LOGRAPHY. 

1.  GENERAL  REMARKS  ON  CRYSTALLIZATION. 

THE  attraction  which  produces  crystals  is  one  of  the 
fundamental  properties  of  matter.  It  is  identical  with  the 
cohesion  of  ordinary  solidification;  for  there  are  few  cases 
outside  of  the  kingdoms  of  life  in  which  solidification  takes 
place  without  some  degree  of  crystallization.  Cohesive  at- 
traction is,  in  fact,  the  organizing  or  structure-making 
principle  in  inorganic  nature,  it  producing  specific  forms 
for  each  species  of  matter,  as  life  does  for  each  living  spe- 
cies. A  bar  of  cast-iron  is  rough  and  hackly  in  surface, 
because  of  the  angular  crystalline  grains  which  the  iron 
assumed  as  solidification  took  place.  A  fragment  of  mar- 


CKYSTALS  OF  SNOW. 

ble  glistens  in  the  sun,  owing  to  the  reflection  of  light 
from  innumerable  crystalline  surfaces,  every  grain  in  the 
mass  having  its  crystalline  structure.  Whe*n  the  cold  of 
winter  settles  over  the  earth  in  the  higher  temperate  and 
colder  latitudes  it  is  the  signal  for  crystallization  over  all 
out-door  nature;  the  air  is  filled  with  crystal  flakes  when 
it  snows;  the  streams  become  coated  with  an  aggregation 


CRYSTALLOGRAPHY.  5 

of  crystals  called  ice;  and  windows  are  covered  with  frost 
because  crystal  has  been  added  to  crystal  in  long  feathered 
lines  over  the  glass — Jack  Frost's  work  being  the  making 
of  crystals.  Water  cannot  solidify  without  crystallizing, 
and  neither  can  iron  nor  lead,  nor  any  mineral  material, 
with  perhaps  half  a  dozen  exceptions.  Crystallization  pro- 
duces masses  made  of  crystalline  grains  when  it  cannot 
make  distinct  crystals.  Granite  mountains  are  mountains 
of  crystals,  each  particle  being  crystalline  in  nature  and 
structure.  The  lava  current,  as  it  cools,  becomes  a  mass 
of  crystalline  grains.  In  fact  the  earth  may  be  said  to 
have  crystal  foundations;  and  if  there  is  not  the  beauty  of 
external  form,  there  is  everywhere  the  interior,  profounder 
beauty  of  universal  law — the  same  law  of  symmetry  which, 
when  external  circumstances  permit,  leads  to  the  perfect 
crystal  with  regular  facets  and  angles. 

Crystals  are  alone  in  making  known  the  fact  that  this 
law  of  symmetry  is  one  of  the  laws  of  cohesive  attraction, 
and  that  under  it  this  attraction  not  only  brings  the  par- 
ticles of  matter  into  forms  of  mathematical  symmetry,  but 
often  develops  scores  of  brilliant  facets  over  their  surface 


with  mathematical  exactness  of  angle,  and  the  simplest  of 
numerical  relations  in  their  positions.  Crystals  teach  also 
the  more  wonderful  >fact  that  the  same  species  of  matter 


CRYSTALLOGRAPHY. 


may  receive,  under  the  action  of  this  attraction,  through 
some  yet  incomprehensible  changes  in  its  condition,  a  great 
diversity  of  forms — from  the  solid  of  half  a  dozen  planes 
£o  one  of  scores.  The  above  figures  represent  a  few  of  the 
forms  in  a  common  species,  pyrite,  a  compound  of  iron 
and  sulphur. 


8. 


10. 


Many  more  figures  might  be  given  for  this  one  species, 
pyrite.  The  various  forms  or  planes  in  any  such  case  have, 
it  is  true,  mutually  dependent  relations — a  fact  often  ex- 


CRYSTALLOGRAPHY.  7 

pressed  by  saying  that  they  have  a  common  fundamental 
form.  But  it  is  none  the  less  a  remarkable  fact,  giving  pro- 
found interest  to  the  subject,  that  the  attraction,  while 
having  this  degree  of  unity  in  any  species,  still,  under  each, 
admits  of  the  multitudinous  variations  needed  to  produce 
so  diverse  results. 

At  the  time  of  crystallization  the  material  is  usually  in  a 
state  of  fusion,  or  of  gas  or  vapor,  or  of  solution.  In  the 
case  of  iron  the  crystallization  takes  place  from  a  state  of 
fusion,  and  while  the  result  is  ordinarily  only  a  mass  of 
crystalline  grains,  distinct  crystals  are  sometimes  formed  in 
any  cavities.  If  in  the  cooling  of  a  crucible  of  melted  lead, 
bismuth,  or  sulphur  the  crust  be  broken  soon  after  it  forms, 
and  the  liquid  part  within  be  turned  out,  crystals  will 
be  found  covering  the  interior.  Here,  also,  is  crystalliza- 
tion from  a  state  of  fusion.  When  frost  or  snow-flakes 
form  it  exemplifies  crystallization  from  a  state  of  vapor. 
If  a  saturated  solution  of  alum,  made  with  hot  water,  be 
left  to  cool,  crystals  of  alum  after  a  while  will  appear, 
and  will  become  of  large  size  if  there  is  enough  of  the 
solution.  A  solution  of  common  salt,  or  of  sugar,  affords 
crystals  in  the  same  way.  Again,  whenever  a  mineral  is 
produced  through  the  change  or  decomposition  of  another, 
and  at  the  same  time  assumes  the  solid  state,  it  takes  at 
once  a  crystalline  structure,  if  it  does  not  also  develop  crys^ 
tals. 

Further,  the  crystalline  texture  of  a  solid  mass  may  often 
be  changed  without  fusion :  e.g.,  in  tempering  steel  the 
bar  is  changed  from  coarse-grained  steel  to  fine-grained  by 
heating  and  then  cooling  it  suddenly  in  cold  water,  and 
vice  versa,  and  this  is  a  change  in  every  grain  throughout 
the  bar. 

Thus  the  various  processes  of  solidification  are  processes 
of  crystallization,  and  the  most  universal  of  all  facts  about 
minerals  is  that  they  are  crystalline  in  texture.  A  few  ex- 
ceptions have  been  alluded  to,  and  one  example  of  these  is 
the  mineral  opal,  in  which  even  the  microscope  detects  no 
evidence  of  a  crystalline  condition,  except  sometimes  in 
minute  portions  supposed  not  to  be  opal.  But  if  we  ex- 
clude coals  and  resins  this  mineral  stands  almost  alone. 
Such  facts,  therefore,  do  not  affect  the  conclusion  that  a 
knowledge  of  crystallography  is  of  the  highest  importance 
to  the  mineralogist.  It  is  important  because — 


8  CKYSTALLOGRAPHY. 

1.  A  study  of  the  crystalline  forms  and  structure  of 
minerals  is  a  convenient  means  of  distinguishing  species — 
the  crystals  of  a  species  being  essentially  constant  in  struc- 
ture and  in  angles. 

2.  The  most  important  optical  characters  depend  on  the 
crystallization,  and  have  to  be  learned  from  crystals. 

3.  The  profoundest  chemical  relations  of  minerals  are 
often  exhibited  in  the  relations  of  their  crystalline  forms. 

4.  Crystallization  opens  to  us  Nature  at  her  foundation 
work,  and  illustrates  its  mathematical  character. 


2.  DESCRIPTIONS  OF  CEYSTALS. 

In  describing  crystals  there  are  two  subjects  for  con- 
sideration :  First,  FORM  ;  and  secondly,  STEUCTUEE. 

A.  FOEM. — Under  form  come  up  for  description,  not 
only  the  general  forms  of  crystals,  but  also — 

(1)  The  systems  of  crystallization,  'that  is,  the  relations 
of  all  crystalline  forms,  and  their  classification. 

(2)  The  mutual  relations  of  the  planes  of  a  crystal  as 
ascertained  through  their  positions  and  the  angles  between 
them. 

(3)  The  distortions  of  crystals.     The  perfection  of  sym- 
metry exhibited  in  the  figures  of  crystals,   in  which  all 
similar  planes  are  represented  as  having  the  same  size  and 
form,  is  seldom  found  in  nature,  and  the  true  form  is  often 
greatly  disguised  by  this  means.     The  facts  on  this  point, 
and  the  methods  of  avoiding  wrong  conclusions,  need  to  be 
understood,  and  these  are  given  beyond.     With  all  such 
imperfections  the  angles  of  crystals  remain  essentially  con- 
stant.    There  are  irregularities  also  from  other  sources. 

(4)  Twin  or  compound   crystals.      With   some  species 
twins  are  more  common  than  regular  crystals. 

(5)  Crystalline  aggregates,  or  combinations  of  imperfect 
crystals,  or  of  crystalline  grains. 

Explanations  of  Terms. 

The  following  are  explanations  of  a  few  terms  used  in  connection 
with  this  subject: 

1.  Octahedron. — A  solid  bounded  by  eight  equal  triangles.  They 
are  equal  equilateral  triangles  in  the  regular  octahedron  (Fig.  2,  p.  18) ; 
equal  isosceles  triangles  in  the  square  octahedron  (Fig.  17,  p.  33) ; 
equal  inequilateral  triangles  in  the  rhom&ic  octahedron  (Fig.  8,  p.  38). 


CRYSTALLOGRAPHY.  9 

2.  Double  six-sided  pyramids.    Double  eight-sided  pyramids.    Double 
twelve-sided  pyramids. — Solids  made  of  two  equilateral  six-sided,  or 
eight-sided,  or  twelve-sided,  pyramids  placed  base  to  base  (Fig.  20,  p. 
33,  and  6,  10,  pp.  48,  49). 

3.  Eight  prisons.     Oblique  prisms.— Right  prisms  are  those  that  are 
erect,  all  their  sides  being  at  right  angles  to  the  base.    When  inclined, 
they  are  calkd  oblique  prisms. 

4.  Interfacial  angle. — Angle  of  inclination  between  two  faces  or 
planes. 

5.  Similar  planes.     Similar  angles. — The  lateral  faces  of  a  square 
prism  (Fig.  2,  p.  15)  are  equal  and  have  like  relations  to  the  axes,  and 
hence  they  are  said  to  be  similar.     Solid  angles  are  similar  when  the 
plane  angles  are  equal  each  for  each,  and  the  enclosing  planes  are  sev- 
erally similar  in  their  relations  to  the  axes. 

6.  Truncated.    Bevelled. — An  edge  of  a  crystal  is  said  to  be  trun- 
cated when  it  is  replaced  by  a  plane  equally  inclined  to  the  enclosing 
planes,  as  in  Fig.  13,  p.  20  ;  and  it  is  bevelled  when  -replaced  by  two 
planes  equally  inclined  severally  to  the  adjoining  faces.     Only  edges 
that  are  formed  by  the  meeting  of  two  similar  planes  can  be  truncated 
or  bevelled.     The  angle  between  the  truncating  plane  and  the  plane 
adjoining  it  on  either  side  always  equals  90°  plus  half  the  interfacial 
angle  over  the  truncated  edge.     When  a  rectangular  edge,  or  one  of 
90U,  is  truncated,  this  angle  is  accordingly  135°  (=  90°  -j-  45D) ;  when 
an  edge  of  70°,  it  is  125°  (=  90°  -f-  35°) ;  when  an  edge  of  140°,  it  is 
160°  (=90° +  70°). 

7.  Zone. — A  zone  of  planes  includes  a  series  of  planes  having  the 
edges  between  them,  that  is,  their  mutual  intersections,  all  parallel. 
Thus  in  Fig.  14,  on  page  6,  JET  at  top  of  figure,  i2,  i\,  H  in  front,  and 
two  planes  below,  and  others  on  the  back  of  the  crystal  are  in  one  zone, 
a  vertical  zone.     Again,  in  the  same  figure,  H  at  top,  42,  3|,  22,  42,  i2, 
42,  22,  3f ,  and  the  continuation  of  this  series  below  and  over  the  back 
of  the  crystal  lie    in  another  vertical  zone.      And  so  in  cases  in 
other  directions.    All  planes  in  the  same  zone  may  be  viewed  as  on  the 
circumference  of  the  same  circle.    The  planes  of  crystals  are  generally 
all  comprised  in  a  few  zones,  and  the  study  of  the  mathematics  of 
crystals  is  largely  the  study  of  zones  of  planes. 

Axes. — Imaginary  lines  in  crystals  intersecting  one  another  at  their 
centres.  Axes  are  assumed  in  order  to  describe  the  positions  of  the 
planes  of  crystals.  In  each  system  of  crystallization  there  is  one  verti- 
cal axis,  and  in  all  but  hexagonal  forms  there  are  two  lateral  axes. 

Diametral  sections. — The  sections  of  crystals  in  which  lie  any  two  of 
the  axes.  In  forms  having  two  lateral  axes,  there  are  two  vertical 
diametral  sections  and  one  basal. 

Diametral  prisms. — Prisms  whose  sides  are  parallel  to  the  diametral 
sections. 


The  angles  of  crystals  are  measured  by  means  of  instruments  called 
goniometers.  These  instruments  are  of  two  kinds,  one  the  common 
goniometer,  the  other,  the  reflecting  goniometer. 


10 


C  R  YST  A  LLOGRAPHY. 


The  common  goniometer  depends  for  its  use  on  the  very  simple  prin- 
ciple that  when  two  straight  lines  cross  one  an- 
4:  ^p  other,  as  AE,  CD,  in  the  annexed  figure,  the  parts 

^N\^^-'x'  will  diverge  equally  on  opposite  sides  of  the  point 
.^-^3\^^  of  intersection  (O);  that  is,  in  mathematical  lan- 
c-"^  \E  guage,  the  angle  AOD  is  equal  to  the  angle  COE, 

and  AO G  is  equal  to  DOE. 

A  common  form  of  the  instrument  is  represented  in  the  figure  be- 
low. 

The  two  arms  ab,  cd,  move  on  a  pivot  at  o,  and  their  divergence, 
or  the  angle  they  make  with  one  another,  is  read  off  on  the  graduated 
arc  attached.  In  using  it,  press  up  between  the  edges  ao  and  co 
the  edge  of  the  crystal  whose  angle  is  to  be  measured,  and  con- 
tinue thus  opening  the  arms  until  these  edges  lie  evenly  against  the 
faces  that  include  the  required  angle.  To  insure  accuracy  in  this 
respect,  hold  the  instrument  and  crystal  between  the  eye  and  the  light, 
and  observe  that  no  light  passes  between  the  arm  and  the  applied  faces 
of  the  crystal.  The  arms  may  then  be  secured  in  position  by  tighten- 
ing the  screw  at  <?;  the  angle  will  then  be  measured  by  the  distance  on 
the  arc  from  If  to  the  left  or  outer  edge  of  the  arm  cd,  this  edge  being 
in  the  line  of  o,  the  centre  of  motion.  As  the  instrument  stands  in  the 
figure,  it  reads  45°.  The  arms  have  slits  at  gh,  np,  by  which  the 
parts  ao,  co,  may  be  shortened  so  as  to  make  them  more  convenient 
for  measuring  small  crystals. 

In  the  best  form  of  the  common  goniometer  the  arc  is  a  complete 


circle,  of  larger  diameter  than  in  the  above  figure,  and  the  arms  are 
separate  from  it.  After  making  the  measurement,  the  arms  are  laid 
upon  the  circle,  with  the  pivot  at  the  centre  of  motion  inserted  in  a 
socket  at  the  centre  of  the  circle.  The  inner  edge  of  one  of  the  arms 
is  then  brought  to  zero  on  the  circle,  and  the  angle  is  read  off  as  be- 
fore. 


CRYSTALLOGRAPHY.  11 

With  a  little  ingenuity  the  student  may  construct  a  goniometer  for 
himself  that  will  answer  a  good  purpose.  A  semicircle  may  be  de- 
scribed on  mica  or  a  glazed  card,  and  graduated.  The  arms  might 
also  be  made  of  stiff  card  for  temporary  use;  but  mica,  bone,  or  metal 
is  better.  The  arms  should  have  the  edges  straight  and  accurately 
parallel,  and  be  pivoted  together.  The  instrument  may  be  used  like 
that  last  described,  and  will  give  approximate  results,  sufficiently  near 
for  distinguishing  most  minerals.  The  ivory  rule  accompanying  boxes 
of  mathematical  instruments,  having  upon  it  a  scale  of  sines  for  measur- 
ing angles,  will  answer  an  excellent  purpose,  and  is  as  convenient  as 
the  arc. 

In  making  such  measurements  it  is  important  to  have  in  mind  the 
fact  that— 

1.  The  sum  of  the  angles  about  a  centre  is  360°. 

2.  In  a  rhomb,  as  in  a  square,  the  sum  of  the  plane  angles  is 
360°. 

In  any  polygon,  the  supplements  of  the  angles  equal  360°,  whatever 
the  number  of  sides.  For  example:  in  a  square,  the  four  angles  are 
each  90°,  and  hence  the  supplements  are  90°,  and  4x90=360;  again, 
in  a  regular  hexagon  the  six  angles  are  each  120,  the  supplements  are 
60°,  and  6x60=360.  So  for  all  polygons,  whether  regular  or  irregular. 
In  measuring  the  angles  it  is  therefore  convenient  to  take  down  the 
supplements  of  the  angles.  This  principle  is  conveniently  applied  in 
the  measurement  of  all  the  angles  of  a  zone  of  planes  around  the 
crystal ;  for  the  sum  of  all  the  supplements  should  be,  as  above,  360°, 
and  if  this  result  is  not  obtained  there  is  error  somewhere. 

The  reflecting  goniometer  affords  a  more  accurate  method  of 
measuring  crystals  that  have  lustre,  and  may  be  iised  with  those  of 
minute  size.  The  principle  on  which  this  instrument  is  constructed 
will  be  understood  from  the  annexed  figure,  representing  a  crystal, 
whose  angle  abc  is  required.  The  eye,  look- 
ing at  the  face  of  the  crystal  be,  observes  a 
reflected  image  of  m,  in  the  direction  Pn.  On 
revolving  the  crystal  till  ab  has  the  position  of 
be,  the  same  image  will  be  seen  again  in  the 
same  direction  Pn.  As  the  crystal  is  turned, 
in  this  revolution,  till  abd  has  the  present 
position  of  be,  the  angle  dbc  measures  the 
number  of  degrees  through  which  it  is  revolved.  But  dbc  subtracted 
from  180°  equals  the  angle  of  the  crystal  abc.  The  crystal  is  there- 
fore passed,  in  its  revolution,  through  a  number  of  degrees  equal  to 
the  supplement  of  the  required  angle. 

This  angle,  in  the  reflecting  goniometer  of  Wollaston,  one  form  of 
which  is  represented  in  the  following  figure,  is  measured  by  attaching 
the  crystal  to  a  graduated  circle  which  revolves  with  it. 

C  is  the  graduated  circle.  The  wheel,  m,  is  attached  to  the  main 
axis,  and  moves  the  graduated  circle  together  with  the  adjusted  crys- 
tal. The  wjieel,  n,  is  connected  with  an  axis  which  passes  through 
the  main  axis  (which  is  hollow  for  the  purpose),  and  moves  merely  the 
parts  to  which  the  crystal  is  attached,  in  order  to  assist  in  its  adjust- 
ment. The  contrivances  for  the  adjustment  of  the  crystal  are  at  a,  b, 
c,  d,  k.  The  screws,  c,  d,  are  for  the  adjustment  of  the  crystal,  and 
the  slides,  a,  b,  serve  to  centre  it. 


1/5  CRYSTALLOGRAPHY. 

To  use  the  instrument,  it  may  be  put  on  a  stand  or  small  table,  with 
its  base  accurately  horizontal,  and  the  table  placed  in  front  of  a  win- 
dow, six  to  twelve  feet  off,  with  the  plane  of  its  circle  at  right  angles 
to  the  window.  A  line  must  then  be  drawn  below  the  window,  near 
or  on  the  floor,  parallel  to  the  bars  of  the  window,  and  about  as  far 
from  the  eye  as  from  the  window-bar. 

The  crystal  is  attached  to  the  movable  plate  &  by  means  of  wax,  and 
so  arranged  that  the  edge  of  intersection  of  the  two  planes  forming  the 


required  angle  shall  be  in  a  line  with  the  axis  of  the  instrument. 
This  is  done  by  varying  its  situation  on  the  plate,  or  by  means  of  the 
adjacent  screws  and  slides. 

When  apparently  adjusted,  the  eye  must  be  brought  close  to  the 
crystal,  nearly  in  contact  with  it,  and  on  looking  into  a  face,  part  of 
the  window  will  be  seen  reflected,  one  bar  of  which  must  be  selected 
for  the  trial.  If  the  crystal  is  correctly  adjusted,  the  selected  bar 
will  appear  horizontal,  and  on  turning  the  wheel  n,  till  this  bar,  as 
reflected,  is  observed  to  approach  the  dark  line  below  seen  in  a  direct 
view,  it  will  be  found  to  be  parallel  to  this  dark  line,  and  ultimately  to 
coincide  with  it.  The  eye  for  both  observations  should  be  held  in 


CRYSTALLOGKAPHY.  13 

precisely  the  same  position.  If  there  is  not  a  perfect  coincidence,  the 
adjustment  must  be  altered  until  this  coincidence  is  obtained.  Con- 
tinue then  the  revolution  of  the  wheel  n,  till  the  same  bar  is  seen  by 
reflection  in  the  next  face,  and  if  here  there  is  also  a  coincidence  of 
the  reflected  bar  with  the  dark  line  seen  direct,  the  adjustment  is  com- 
plete; if  not,  alterations  must  be  made,  and  the  first  face  again  tried. 
In  an  instrument  like  the  one  figured,  the  circle  is  usually  graduated 
to  twenty  or  thirty  minutes,  and,  by  means  of  the  vernier,  minutes  and. 
half  minutes  are  measured.  After  adjustment,  180°  on  the  arc  must 
be  brought  opposite  0,  on  the  vernier,  v.  The  coincidence  of  the  bar 
and  dark  line  is  then  to  be  obtained,  by  turning  the  wheel  n.  When 
obtained,  the  wheel  m  should  be  turned  until  the  same  coincidence  is 
observed,  by  means  of  the  next  face  of  the  crystal.  If  a  line  on  the 
graduated  circle  now  corresponds  with  0  on  the  vernier,  the  angle  is 
immediately  determined  by  the  number  of  degrees  opposite  this  line. 
If  no  line  corresponds  with  0,  we  must  observe  which  line  on  the 
vernier  coincides  with  one  on  the  circle.  If  it  is  the  18th  on  the 
vernier,  and  the  line  on  the  circle  next  below  0  on  the  vernier  marks 
125°,  the  required  angle  is  125°  18';  if  this  latter  line  marks  125°  20', 
the  required  angle  is  125°  38'. 

In  the  better  instruments  other  improved  methods  of  arrangement 
are  employed;  and  in  the  best,  often  called  Mitscherlich's  goniometer, 
because  first  devised  by  him,  there  are  two  telescopes,  one  for  passing 
a  ray  of  light  upon  the  adjusted  crystal,  having  crossed  hair-lines  in  its 
focus,  and  the  other  for  viewing  it,  also  with  a  hair-cross.  With  such 
an  arrangement,  the  window-bar  and  dark  line  are  unnecessary,  the 
hair-crosses  serving  to  fix  the  position  of  the  crystal,  and  the  telescope 
that  of  the  eye.  If  the  crystal  is  perfect  in  its  planes,  and  the  adjust- 
ment exact,  the  measurement,  with  the  best  instruments,  will  give  the 
angle  within  10". 

Other  goniometers  have  only  the  second  of  the  two  telescopes  just 
alluded  to,  as  is  the  case  in  the  figure  on  page  12.  This  telescope  gives 
a  fixed  position  to  the  eye;  and  through  it  is  seen  a  reflection  of  some 
distant  object,  which  may  be  even  a  chimney-top.  For  the  measure- 
ment the  object,  seen  reflected  in  the  two  planes  successively,  is 
brought  each  time  into  conjunction  with  the  hair  cross.  Exact  ad- 
justment is  absolutely  essential,  and  with  an  instrument  having  the  two 
telescopes,  the  first  step  in  a  measurement  cannot  be  taken  without  it. 

Only  small,  well-polished  crystals  can  be  accurately  measured  by  the 
reflecting  goniometer.  If,  when  using  the  instrument  without  tele- 
scopes, the  faces  do  not  reflect  distinctly  a  bar  of  the  window,  the 
flame  of  a  candle  or  of  a  gas-burner,  placed  at  some  distance  from  the 
crystal,  may  be  used  by  observing  the  flash  from  it  with  the  faces  in 
succession  as  the  circle  is  revolved.  A  ray  of  sunlight  from  a  mirror, 
received  on  the  crystal  through  a  small  hole,  may  be  employed  in  a 
similar  way.  But  the  results  of  such  measurements  will  be  only 
approximations.  With  two  telescopes  and  artificial  light,  and  with  a 
cross-slit  to  let  the  light  pass  in  place  of  the  cross-hairs  of  the  first  of 
the  above  mentioned  telescopes,  this  light  cross  will  be  reflected  from 
the  face  of  a  crystal  even  when  it  is  not  perfect  in  polish,  and  quite 
good  results  may  be  obtained. 


14  CRYSTALLOGRAPHY. 

B.  STRUCTURE. — Structure  includes  cleavage,  a  charac- 
teristic of  crystals  intimately  connected  with  their  forms 
and  nature.  It  is  the  property,  which  many  crystals  have, 
of  admitting  of  subdivision  indefinitely  in  certain  directions, 
and  affording  usually  even,  and  frequently  polished,  sur- 
faces. The  direction  is  always  parallel  with  the  planes  of 
the  axes,  or  with  others  diagonal  to  these. 

The  ease  with  which  cleavage  can  be  obtained  varies 
greatly  in  different  minerals,  and  in  different  directions  in 
the  same  mineral.  In  a  few  species,  like  mica,  it  readily 
yields  laminae  thinner  than  paper,  and  in  this  case  the 
cleavage  is  said  to  be  eminent.  Others,  of  perfect  cleavage, 
cleave  easily,  but  afford  thicker  plates,  and  from  this  stage 
there  are  all  grades  to  that  in  which  cleavage  is  barely  dis- 
cernible or  difficult.  The  cleavage  surfaces  vary  in  lustre 
from  the  most  brilliant  to  those  that  are  nearly  dull.  When 
cleavage  in  a  mineral  is  alike  in  two  or  more  directions, 
that  is,  is  attainable  in  these  directions  with  equal  facility 
and  affords  surfaces  of  like  lustre  and  character  or  mark- 
ing, this  is  proof  that  the  planes  in  those  directions  are 
similar,  or  have  similar  relations  to  like  axes.  For  ex- 
ample, equal  cleavage  in  three  directions,  at  right  angles  to 
one  another,  shows  that  the  planes  of  cleavage  correspond 
to  the  faces  of  the  cube;  so  equal  cleavage  in  two  directions, 
in  a  prismatic  mineral,  shows  that  the  planes  in  the  two 
directions  are  those  of  a  square  prism,  or  else  of  a  rhombic 
prism;  and  if  they  are  at  right  angles  to  one  another,  that 
they  are  those  of  the  former.  This  subject  is  further  illus- 
trated beyond. 


In  the  following  pages  (1)  the  Systems  of  Crystallization 
and  the  Forms  and  Structure  of  Crystals  are  first  con- 
sidered; next,  (2)  Compound  or  Twin  Crystals ;  (3)  Para- 
morphs;  (4)  Pseudomorphs ;  and  (5)  Crystalline  Aggre- 
gates. 


SYSTEMS   OF   CRYSTALLIZATION-. 


15 


1.  SYSTEMS  OF  CRYSTALLIZATION:  FORMS 
AND  STRUCTURE  OF  CRYSTALS. 

The  forms  of  crystals  are  exceedingly  various,  while  the 
systems  of  crystallization,  based  on  their  mathematical  dis- 
tinctions, are  only  six  in  number.  Some  of  the  simplest  of 
the  forms  under  these  six  systems  are  the  prisms  represented 
in  the  following  figures;  and  by  a  study  of  these  forms  the 


distinctions  of  the  six  systems  will  become  apparent.  These 
prisms  are  all  four-sided,  excepting  the  last,  which  is  six- 
sided.  In  them  the  planes  of  the  top  and  bottom,  and  any 
planes  that  might  be  made  parallel  to  these,  are  called  the 
basal  planes,  and  the  sides  the  lateral  planes.  An  imaginary 
line  joining  the  centres  of  the  bases  (c  in  Figs.  1  to  8)  is 
called  the  vertical  axis,  and  the  diagonals  a  and  1),  drawn 
in  a  plane  parallel  to  the  base,  are  the  lateral  axes. 

Fig.  1  represents  a  cube.  It  has  all  its  planes-  square 
(like  Fig.  9),  and  all  its  plane  arid  solid  angles,  right  angles, 
and  the  three  axes  consequently  cross  at  right  angles  (or,  in 
other  words,  make  rectangular  intersections)  and  are  equal. 
It  is  an  example  under  the  first  of  the  systems  of  crystalli- 
zation, which  system,  in  allusion  to  the  equality  of  tho  axes, 
is  called  the  Isometric  system,  from  the  Greek  for  equal 
and  measure. 

Fig.  2  represents  an  erect  or  right  square  prism  having 


16  CRYSTALLOGKAPHY. 

all  its  plane  angles  and  solid  angles  rectangular.  The  base 
is  square  or  a  tetragon,  and  consequently  the  lateral  axes 
are  equal  and  rectangular  in  their  intersections;  but,  unlike 
a  cube,  the  vertical  axis  is  unequal  to  the  lateral.  There 
are  hence,  in  the  square  prism,  axes  of  two  kinds  making 
rectangular  intersections.  The  system  is  hence  called,  in 
allusion  to  the  tetragonal  base,  the  Tetragonal  system. 

Fig.  3  represents  an  erect  or  right  rectangular  prism,  in 
which,  also,  the  -plane  angles  and  solid  angles  a^e  rectangu- 

9. 


lar.  The  base  is  a  rectangle  (Fig,  10),  and  consequently  the 
lateral  axes,  connecting  the  centres  of  the  opposite  lateral 
faces,  are  unequal  and  rectangular  in  their  intersections ; 
and,  at  the  same  time,  each  is  unequal  to  the  vertical. 
There  are  hence  three  unlike  axes  making  rectangular  in- 
tersections ;  and  the  system  is  called,  in  allusion  to  the 
three  unlike  axes  and  in  allusion  also  to  its  including  erect 
prisms  having  a  rhombic  base,  the  Orthorhombic  system, 
orthos,  in  Greek,  signifying  straight  or  erect. 

This  rhombic  prism  is  represented  in  Fig.  4.  It  has  a 
rhombic  base,  like  Fig.  11 ;  the  lateral  axes  connect  the 
centres  of  the  opposite  lateral  edges  ;  and  hence  they  cross 
at  right  angles  and  are  unequal,  as  in  the  rectangular  prism. 
This  right  rhombic  prism  is  therefore  one  in  system  with 
the  right  rectangular  prism. 

Fig.  5  represents  another  rectangular  prism,  and  Fig.  6 
another  rhombic  prism ;  but,  unlike  Figs.  3  and  4,  the  prisms 
are  inclined  backward,  and  are  therefore  oblique  prisms. 
The  lateral  axes  (a,  b)  are  at  right  angles  to  one  another  and 
unequal,  as  in  the  preceding  system ;  but  the  vertical  axis 
is  inclined  to  the  plane  of  the  lateral  axes.  It  is  inclined, 
however,  to  only  one  of  the  lateral  axes,  it  being  at  right 
angles  to  the  other.  Hence,  of  the  three  angles  of  axial 
intersection,  two  are  rectangular,  namely,  a  on  b,  and  c  on  b, 
while  one  is  oblique,  that  is,  c  (the  vertical  axis)  on  a.  In 
allusion  to  this  fact,  there  being  only  one  oblique  angle, 


SYSTEMS   OF    CRYSTALLIZATION.  17 

this  system  is  called  the  Monoclinic  system,  from  the  Gree*. 
for  one  and  inclined. 

Fig.  7  represents  an  oblique  prism  with  a  rhomboidal 
base  "(like  Fig.  12).  The  three  axes  are  unequal  and  the 
three  axial  intersections  are  all  oblique.  The  system  is 
called  the  Triclinic  system,  from  the  Greek  for  three  and 
inclined. 

Fig.  8  represents  a  six-sided  prism,  with  the  sides  equal 
and  the  base  a  regular  hexagon.  The  lateral  axes  are  here 
three  in  number.  They  intersect  at  angles  of  60° ;  and 
this  is  so,  whether  these  lateral  axes  be  lines  joining  the 
centres  of  opposite  lateral  planes,  or  of  opposite  lateral 
edges,  Us  a  trial  will  show.  The  vertical  axis  is  at  right 
angles  to  the  plane  of  the  three  lateral  axes,  inasmuch  as 
the  prism  is  erect  or  right.  The  base  of  the  prism  being  a 
regular  hexagon,  the  system  is  called  the  Hexagonal  system. 

The  systems  of  crystallization  are  therefore  : 

I.  The  ISOMETRIC  system  :  the  three  axes  rectangular  in 
intersections ;  equal. 

II.  The  TETRAGONAL  system :  the  three  axes  rectangular 
in  intersections  ;  the  two  lateral  axes  equal,  and  unequal  to 
the  vertical. 

III.  The  ORTHORHOMBIC  system  :  the  three  axes  rectan- 
gular in  intersections,  and  unequal. 

IV.  The  MONO-CLINIC  system :  only  one  oblique  inclina- 
tion out  of  the  three  made  by  the  intersecting  axes ;  the 
three  axes  unequal. 

V.  The  TRICLINIC  system :  all  the  three  axes  obliquely 
inclined  to  one  another,  and  unequal. 

VI.  The  HEXAGONAL  system  :  the  vertical  axis  at  right 
angles  to  the  lateral ;  the  lateral  three  in  number,  and  in- 
tersecting at  angles  of  60°. 

These  six  systems  of  crystallization  are  based  on  mathe- 
matical distinctions,  and  the  recognition  of  them  is  of  great 
value  in  the  study  and  description  of  crystals.  Yet  these 
distinctions  are  often  of  feeble  importance,  since  they  some- 
times separate  species  and  crystalline  forms  that  are  very 
close  in  their  relations.  There  are  forms  under  each  of 
the  systems  that  differ  but  little  in  angles  from  some  of 
other  systems :  for  example,  square  prisms  that  vary  but 
slightly  from  the  cubic  form ;  triclinic  that  are  almost  iden- 
tical with  monoclinic  forms ;  hexagonal  that  are  nearly  cu- 
bic. Consequently  it  is  found  that  the  same  natural  group 
2 


18 


CRYSTALLOGRAPHY. 


of  minerals  may  include  both  orthorhombic  and  mono- 
clinic  species,  as  is  true  of  the  Hornblende  group ;  or  mono- 
clinic  and  triclinic,  as  is  the  fact  with  the  Feldspar  group,, 
and  so  on.  It  is  hence  a  point  to  be  remembered,  when 
the  affinities  of  species  are  under  consideration,  that  differ- 
ence in  crystallographic  system  is  far  from  certain  evidence 
that  any  species  are  fundamentally  or  widely  unlike. 


I.  THE  ISOMETRIC  SYSTEM. 

1,  Descriptions  of  Forms. — The  following  are  figures  of 
some  of  the  forms  of  crystals  under  the  isometric  system: 


l. 


The  first  is  the  cube  or  hexahedron,  already  described. 
Besides  the  three  cubic  axes,  there  are  equal  diagonals  in 
two  other  directions ;  one  set  connecting  the  apices  of  the 
diagonally  opposite  solid  angles,  four  in  number  (because 
the  number  of  such  angles  is  eight),  and  called  the  octahe- 
dral axes ;  and  another  set  connecting  the  centres  of  the 
diagonally  opposite  edges,  six  in  number  (because  the  num- 
ber of  edges  is  twelve),  and  called  the  dodecahedral  axes. 

Fig.  2  represents  the  octahedron,  a  solid  contained  under 
eight  equal  triangular  faces  (whence  the  name  from  the 
Greek  eight  soldi  face),  and  having  the  three  axes  like  those 
in  the  cube.  Its  plane  angles  are  60°;  its  interfacial  angles, 
that  is,  the  inclination  of  planes  1  and  1  over  an  intervening 


ISOMETRIC   SYSTEM.  19 

edge  (usually  written  1  A  1)  =  109°  28'  (more  exactly  109° 
28'  16");  and  1  on  1  over  a  solid  angle,  70°  32'. 

Fig.  3  is  the  dodecahedron,  a  solid  contained  under  twelve 
equal  rhombic  faces  (whence  the  name  from  the  Greek  for 
twelve  and  face).  The  position  of  the  cubic  axes  is  shown 
in  the  figure.  It  has  fourteen  solid  angles  ;  six  formed  by 
the  meeting  of  four  planes,  and  eight  formed  by  the  meet- 
ing of  three.  The  interfacial  angles  (or  i  on  an  adjoining 
i)  are»120°;  i  on  *  over  a  four-faced  solid  angle  =  90°. 

Fig.  4  is  a  trapezoliedron,  a  solid  contained  under  24  equal 
trapezoidal  faces.  There  are  several  different  trapezohe- 
drons  among  isometric  crystalline  forms.  The  one  here 
figured,  which  is  the  common  one,  has  the  angle  over  the 
edge  B,  131°  49',  and  that  over  the  edge  C,  146°  27'.  A 
trapezohedron  is  also  called  a  tetragonal  trisoctahedron,  the 
faces  being  tetragonal  or  four-sided,  and  the  number  of 
faces  being  3  times  8  (tris,  octo,  in  Greek). 

Fig.  5  is  another  trisoctahedron,  one  having  trigonal 
or  three-sided  faces,  and  hence  called  a  trigonal  trisoctaUe- 
dron.  Comparing  it  with  the  octahedron,  Fig.  2,  it  will  be 
seen  that  three  of  its  planes  correspond  to  one  of  the  octa- 
hedron. The  same  is  true  also  of  the  trapezohedron. 

Fig.  6  is  a  tetrahexalicdron,  that  is,  a  4  X  6-f aced  solid, 
the  faces  being  24  in  number,  and  four  corresponding  to 
each  face  of  the  cube  or  hexahedron  (Fig.  1).- 

Fig.  7  is  a  hexoctahedron,  that  is,  a  6  X  8-faced  solid,  a 
pyramid  of  six  planes  corresponding  to  each  face  in  the 
octahedron,  as  is  apparent  on  comparison.  There  are  dif- 
ferent kinds  of  hexoctahedrons  known  among  crystallized 
isometric  species,  as  well  as  of  the  two  preceding  forms. 
In  each  case  the  difference  is  not  in  number  or  general  ar- 
rangement of  planes,  but  in  the  angles  between  the  planes, 
as  explained  beyond. 

But  these  simple  forms  very  commonly  occur  in  combina- 
tion with  one  another ;  a  cube  with  the  planes  of  an  octahe- 
dron and  the  reverse,  or  with  the  planes  of  any  or  all  of  the 
other  kinds  above  figured,  and  many  others  besides.  More- 
over, all  stages  between  the  different  forms  are  often  repre- 
sented among  the  crystals  of  a  species.  Thus  between  the 
cube  and  octahedron  occur  the  forms  shown  in  Figs.  8  to 
11.  Fig.  12  is  a  cube ;  Fig.  8  represents  the  cube  with  a 
plane  on  each  angle,  equally  inclined  to  each  cubic  face;  9, 
the  same,  with  the  planes  on  the  angles  more  enlarged 


20 


CRYSTALLOGRAPHY. 


the  cubic  faces  reduced  in  size ;  and  then  10,  the  octahe- 
dron, with  the  cubic  faces  quite  small;  and  Fig.  11,  the 
octahedron,  the  cubic  faces  having  disappeared  altogether. 
This  transformation  is  easily  performed  by  the  student  with 
cubes  cut  out  of  chalk,  clay,  or  a  potato.  It  shows  the  fact 


8. 


that  the  cubic  axes  (Fig.  12)  connect  the  apices  of  the  solid 
angles  in  the  octahedron. 

Again,  between  a  cube  and  a  dodecahedron  there  occur 
forms  like  Figs.  13  and  14 ;  Fig.  12  being  a  cube,  Fig.  13  the 
same,  with  planes  truncating  the  edges,  each  plane  being 
equally  inclined  to  the  adjacent  cubic  faces,  and  Fig.  14  an- 
other, with  these  planes  on  the  edges  large  and  the  cubic 
faces  small ;  and  then,  when  the  cubic  faces  disappear  by 
further  enlargement  of  the  planes  on  the  edges,  the  form  is 
a  dodecahedron,  Fig.  15.  The  student  should  prove  this 
transformation  by  trial  with  chalk  or  some  other  material, 
and  so  for  other  cases  mentioned  beyond.  The  surface  of 
such  models  in  chalk  may  be  made  hard  by  a  coat  of  muci- 
lage or  varnish. 

Again,  between  a  cube  and  a  trapezohedron  there  are  the 
forms  17  and  18 ;  16  being  the  cube  ;  IjB,  cube  with  three 
planes  placed  symmetrically  on  each  angle ;  18,  the  same 
with  the  cubic  faces  greatly  reduced  (but  also  with  small 
octahedral  faces),  and  19,  the  trapezohedron,  the  cubic 
faces  having  disappeared. 

Again,  Fig.  20  represents  a  cube  with  three  planes  on  each 


ISOMETRIC    SYSTEM. 


angle,  which,  if  enlarged  to  the  obliteration  of  the  faces  of 
the  cube,  become  the  trigonal  trisoctahedron,  Fig.  21.     So 


again,  Fig.  22  represents  a  cube  with  six  faces  on  each  angle, 
which,  if  enlarged  to  the  same  extent  as  in  the  last,  would      X 
become  the  hexoctahedron,  Fig.  23. 

Again,  Fig.  25  is  a  form  between  the  octahedron  (Fig.  24) 


and  dodecahedron  (Fig.  26);  and  Figs.  27  and  28  are  forms 
between  the  dodecahedron,  Fig.  26,  and  trapezohedron, 
Fig.  29. 


CRYSTALLOGRAPHY. 


Again,  Fig.  30  is  a  form  between  a  cube  (Fig.  16)  and  a 
tetrahexahedron,  Fig.  31;  Fig.  32,  a  form  between  an  octa- 
hedron, Fig.  24,  and  a  tetratiexahedron,  Fig.  31;  Fig.  33,  a 

30.  3l!*L  82. 

-h- 


form  between  an  octahedron  and  a  trigonal  trisoctahedron, 
Fig.  34;  Fig.  35,  a  form  between  a  dodecahedron  (planes  ?') 

33.  34.  35. 


and  a  tetrahexahedron;  Fig.  36,  a  form  between  the  dodeca- 
hedron and  a  hexoctahedron,  Fig.  37. 

Fig.  38  represents  a  cube  with  planes  of  both  the  octa- 
hedron and  dodecahedron. 

2.  Positions  of  planes  with  reference  to  the  axes.  Lettering 
of  figures. — The  numbers  by  which  the  planes  in  the  above  figures, 
and  others  of  tife  work,  are  lettered,  indicate  the  positions  of  the  planes 
with  reference  to  the  axes,  and  exhibit  the  mathematical  symmetry  and 
ratios  in  crystallization.  In  the  figure  of  the  cube  (Fig.  1)  the  three  axes 
are  represented;  the  lateral  semi-axis  which  meets  the  front  planes  in  the 
figure  is  lettered  4;  that  meeting  the  side  plane  to  the  right  b,  and  the 
vertical  axis  c,  and  the  other  halves  of  the  same  axes  respectively  -a, 
-I,  -c.  By  a  study  of  the  positions  of  the  planes  of  the  cube  and  other 
forms  with  reference  to  these  axes,  the  following  facts  will  become 
apparent. 


ISOMETKIC   SYSTEM.  23 

In  the  cube  (Fig.  1)  the  front  plane  touches  the  extremity  of  axis  a, 
but  is  parallel  to  axes  b  and  c.  When  one  line  or  plane  is  parallel  to 
another  they  do  not  meet  except  at  an  infinite  distance,  and  hence  the 
sign  for  infinity  is  used  to  express  parallelism.  Employing  i,  the  initial 
of  infinity,  as  this  sign,  and  writing  c,  b,  a,  for  the  semi-axes  so  lettered, 
then  the  position  of  this  plane  of  the  cube  is  indicated  by  the  expres- 
sion ic  :  ib  :  la.  The  top  and  side-planes  of  the  cube  meet  one  axis  and 
are  parallel  to  the  other  two,  and  the  same  expression  answers  for  each, 
if  only  the  letters  a,  b,  c,  be  changed  to  correspond  with  their  positions. 
The  opposite  planes  have  the  same  expressions,  except  that  the  c,  b,  a, 
will  refer  to  the  opposite  halves  of  the  axes  and  be  -c,  -b,  -a. 

In  the  dodecahedron,  Fig.  15,  the  right  of  the  two  vertical  front 
planes  i  meets  two  axes,  the  axes  a  and  T),  at  their  extremities,  and  is 
parallel  to  the  axis  c.  Hence  the  position  of  this  plane  is  expressed  by 
ic  :  Ib  :  la.  So,  all  the  planes  meet  two  axes  similarly  and  are  parallel 
to  the  third.  The  expression  answers  as  well  for  the  planes  i  in  Figs. 
13,  14,  as  for  that  of  the  dodecahedron,  for  the  planes  have  all  the 
same  relation  to  the  axes. 

In  the  octahedron,  Fig.  11,  the  face  1  situated  to  the  right  above, 
like  all  the  rest,  meets  the  axes  a,  b,  c,  at  their  extremities;  so  that  the 
expression  -Ic  :lb  :la  answers  for  all. 

Again,  in  Fig.  17  (p.  21)  there  are  three  planes,  2-2,  placed  symmet- 
rically on  each  angle  of  a  cube,  and,  as  has  been  illustrated,  these  are 
the  planes  of  the  trapezohedron,  Fig.  19.  The  upper  one  of  the  planes 
22  in  these  figures,  when  extended  to  meet  the  axes  (as  in  Fig.  19), 
intersects  the  vertical  c  at  its  extremity,  and  the  others,  a  and  b,  at 
twice  their  lengths  from  the  centre.  Hence  the  expression  for  the 
plane  is  Ic  :  2b  :  2a.  So,  as  will  be  found,  the  left-hand  plane  2-2  on 
Fig.  17,  will  have  the  expression  2c  :  Ib  :  2a;  and  the  right-hand  one, 
2c  :  2b  :  la.  Further,  the  same  ratio,  by  a  change  of  the  letters  for  the 
semi-axes,  will  answer  for  all  the  planes  of  the  trapezohedron. 

In  Fig.  20  there  are  other  three  planes,  2,  on  each  of  the  angles  of  a 
cube,  and  these  are  the  planes  of  the  trisoctahedron  in  Fig.  21.  The 
lower  one  of  the  three  on  the  upper  front  solid  angle,  would  meet  if 
extended,  the  extremities  of  the  axes  a  and  b,  while  it  would  meet  the 
vertical  axis  at  twice  its  length  from  the  centre.  The  expression  2c  : 
Ib  :  la  indicates,  therefore,  the  position  of  the  plane.  So  also,  Ic  :  Ib  : 
2a  and  Ic  :  2b  :  la  represent  the  positions  of  'he  other  two  planes  ad- 
joining; and  corresponding  expressions  may  be  similarly  obtained  for 
all  the  planes  of  the  trisoctahedron. 

Again,  in  Fig.  30,  of  the  cube  with  two  planes  on  each  edge,  and  in 
Fig.  31,  of  the  tetrahexahedron  bounded  by  these  same  planes,  the  left 
of  the  two  planes  on  the  front  vertical  edge  of  Fig.  30  (or  the  corre- 
sponding plane  on  Fig.  31)  is  parallel  to  the  vertical  axis;  its  intersections 
with  the  lateral  axes,  a  and  b,  are  at  unequal  distances  from  the  centre, 
expressed  by  the  ratio  2b  :  la.  This  ratio  for  the  plane  adjoining  on 
the  right  is  Ib  :  2a.  The  position  of  the  former  is  expressed  by  the 
ratio  ic:2b-:  la,  and  for  the  other  by  'c  :  Ib  :  2a.  Thus,  for  each  of  the 
planes  of  this  -tetrahexahedron  the  ratio  between  two  axes  is  1  :  2,  while 
the  plane  is  parallel  to  the  third  axis. 

Again,  in  Fig.  22,  of  the  cube  with  six  planes  on  each  solid  angle, 
and  in  the  hexoctahedron  in  Fig.  23,  made  up  of  such  planes,  each  of 
the  planes  when  extended  so  that  it  will  meet  one  axis  at  once  its 


24  CRYSTALLOGRAPHY. 

length  from  the  centre,  will  meet  the  other  axes  at  distances  expressed 
by  a  constant  ratio,  and  the  expression  for  the  lower  right  one  of  the 
six  planes  will  be  3c  :  f  &  :  la.  By  a  little  study,  the  expressions  for  the 
other  five  adjoining  planes  can  be  obtained,  and  so  also  those  for  all 
the  48  planes  of  the  solid. 

In  the  isometric  system  the  axes,  a,  b,  c,  are  equal,  so  that  in  the 
general  expressions  for  the  planes  these  letters  may  be  omitted;  the 
expressions  for  the  above-mentioned  forms  thus  become  — 

Cube  (Fig.  1),  i  :  1  :  *.  Tetrahexahedron  (Fig.  5),  i  :  1  :  2. 

Octahedron  (Fig.  2),  1  :  1  :  1.  Trigonal  trisoctahedron  (Fig.  6), 
Dodecahedron  (Fig.  3),  1  :  1  :  i.  2:1:1. 

Trapezohedron  (Fig.  4),  2  :  1  :  2.  Hexoctahedron  (Fig.  7),  3  :  1  :  f  . 

Looking  again  at  Fig.  17,  representing  the  cube  with  planes  of  the 
trapezobedron,  2  :  1  :  2,  it  will  be  perceived  that  there  might  be  a  tra- 
pezohedron  having  the  ratios  H  :  1  :  1|,  3:1:3,  4:1:4,  5:1:5, 
and  others;  and,  in  fact,  such  trapezohedrons  occur  among  crystals. 
So  also,  besides  the  trigonal  trisoctahedron  2:1:1  (Fig.  21),  there 
might  be,  and  there  in  fact  is,  another  corresponding  to  the  expression 
3  1:1;  and  still  others  are  possible.  And  besides  the  hexoctahedron 


1  :  f  (Fig.  23),  there  are  others  having  the  ratios  4  :  1  :  2,  4  :  1  : 


1  :  |,  and  so  on. 

In  the  above  ratios,  the  number  for  one  of  the  lateral  axes  is  always 
made  a  unit,  since  only  a  ratio  is  expressed;  omitting  this  in  the  ex- 
pression, the  above  general  ratios  become:  for  the  cube,  i  :  i;  for  the 
octahedron,  1:1;  dodecahedron,  1  :  i  ;  trapezohedron,  2:2;  tetra- 
hexahedron,  i  :  2  ;  trigonal-trisoctahedrou,  2:1;  and  hexoctahedron, 
3  :  f  .  In  the  lettering  of  the  figures  these  ratios  are  put  on  the  planes, 
but  with  the  second  figure,  or  that  referring  to  the  vertical  axis,  first, 
Thus  the  lettering  on  the  hexoctahedron  (Fig.  23),  is3-|;  on  the  trigonal 
trisoctahedron  (Fig.  21)  is  2,  the  figure  1  being  unnecessary;  on  the 
tetrahexahedron  (Fig.  31),  i-2  ;  on  the  trapezohedron  (Figs.  4  and  19), 
2-2  ;  on  the  dodecahedron  (Fig.  15),  i  ;  on  the  octahedron,  1  ;  on  the 
cube,  i-i,  in  place  of  which  H  is  used,  the  initial  of  hexahedron.  In 
the  printed  page  these  symbols  are  written  with  a  hyphen  in  order  to 
avoid  occasional  ambiguity,  thus  3-f  ,  i-2,  2-2,  etc.  Similarly,  the 
ratios  for  all  planes,  whatever  they  are,  may  be  written.  The  numbers 
are  usually  small,  and  never  decimal  fractions. 

The  angle  between  the  planes  i-2  (or  i  :  1  :  2)  and  H,  in  Fig.  30,  page 
22,  may  be  easily  calculated,  and  the  same  for  any  plane  of  the  series 
i-n  (i  :  1  :  n).  Draw  the  right-angled  triangle,  ADC, 
as  in  the  annexed  figure,  making  the  vertical  side, 
.CD,  twice  that  of  AC,  the  base;  that  is,  give  them 
the  same  ratio  as  in  the  axial  ratio  for  the  plane.  If 
AC  —  1,  CD  =  2.  Then,  by  trigonometry,  making 
AC  the  radius,  l:E::2:tan  DAG  ;  or  1  :  R  ::  2  :  cot 
ADC.  Whence  tan  DAG  =  cot  ADC  =  2.  By  add- 
ing to  90°,  the  angle  of  the  triangle  obtained  by 
working  the  equation,  we  have  the  inclination  of  the 
basal  plane  H,  on  the  plane  i-2.  So  in  all  cases, 
whatever  the  value  of  n  that  value  equals  the  tangent  of 
the  basal  angle  of  the  triangle  (or  the  cotangent  of  the 
angle  at  the  vertex),  and  from  this  the  inclination  to  the  cubic  faces  is 


ISOMETRIC   SYSTEM.  25 

directly  obtained  by  adding  90°.  If  n  =  1,  then  the  ratio  is  1 : 1,  as 
in  ACS,  and  each  angle  equals  45°,  giving  185°  for  the  inclination  on 
either  adjoining  cubic  face. 

Again  if  the  angles  of  inclination  have  been  obtained  by  measure- 
ment, the  value  of  n  in  any  case  may  be  found  by  reversing  the  above 
calculation;  subtracting  90°  from  the  angle,  then  the  tangent  of  this 
angle,  or  the  cotangent  of  its  supplement,  will  equal  n,  the  tangents 
varying  directly  with  the  value  of  n. 

In  the  case  of  planes  of  the  m  :  1  :  1  series  (including  1:1:1,  2  : 
1:1,  etc.),  the  tangents  of  the  angle  between  a  cubic  face  in  the  same 
zone  and  these  planes,  less  90°,  varies  with  the  value  of  m.  In  the 
case  of  the  plane  1  (or  1  :  1  :  1),  the  angle  between  it  and  the  cubic  face 
is  125°  16'.  Substracting  90°,  we  have  35°  16'.  Draw  a  right-angled 
triangle,  OBG,  with  35°  16'  as  its  vertex  angle.  BO  has 
the  value  of  ic,  or  the  semi-axis  of  the  cube.  Make 
DC  =  2BG.  Then,  while  the  angle  OBG  has  the  value 
of  the  inclination  on  the  cubic  face  less  90°  for  the  plane 
1  :  1  :  1,  ODG  has  the  same  for  the  plane  2:1:1.  Now, 
making  00  the  radius,  and  taking  it  as  unity,  BC  is  the 
tangent  of  BOO,  or  cot  OBO.  So  D0  =  2BG  is  the  tan- 
gent of  DOG,  or  cot  ODG.  By  lengthening  the  side  CD 
(=  2BC  or  2c)  it  may  be  made  equal  to  SBC  =  3c,  its 
value  in  the  case  of  the  plane  3:1:1;  or  to  45(7  =  4c, 
its  value  in  the  case  of  the  plane  4:1:1;  or  mBO  =  me 
for  any  plane  in  the  series  m  :  1  :  1 ;  and  since  in  all 
there  will  be  the  same  relation  between  the  vertical  and 
the  tangent  of  the  angle  at  the  base  (or  the  cotangent  of  the  angle  at 
the  vertex),  it  follows  that  the  tangent  varies  with  the  value  of  m. 
Hence,  knowing  the  value  of  the  angle  in  the  case  of  the  form  1 
(1:1:  1),  the  others  are  easily  calculated  from  it. 

BC  being  a  unit,  the  actual  value  of  OG  is  $  V2~,  or  VJ  it  being 
half  the  diagonal  of  a  square,  the  sides  of  which  are  1,  and  from  this 
value  the  angle  35°  16'  might  be  obtained  for  the  angle  OBG. 

The  above  law  (that,  for  a  plane  of  the  m  :  1  :  1  series,  the  tangent  of 
its  inclination  on  a  cubic  face  lying  in  the  same  zone,  less  90°,  varies 
with  the  value  of  m,  and  that  it  may  be  calculated  for  any  plane 
m :  1  : 1  from  this  inclination  in  the  form  1:1:  1),  holds  also  for 
planes  in  the  series  m  :  2  :  1,  or  m  :  3  :  1,  or  any  m  :  n  :  1.  That  is, 
given  the  inclination  of  0  on  1  :  n  :  1,  its  tangent  doubled  will  be  that 
of  2  :  n  :  1,  or  trebled,  that  of  3  :  n  :  1,  and  so  on  ;  or  halved,  it  will  be 
that  of  the  plane  £ :  n  :  1,  which  expression  is  essentially  the  same  as 
1  :  2n  :  2. 

These  examples  show  some  of  the  simpler  methods  of  applying  ma- 
thematics in  calculations  under  the  isometric  system.  The  values  of 
the  axes  are  not  required  in  them,  because  a  =  b  =  c  =  l. 

3.  Hemihedral  Crystals. — The  forms  of  crystals  described' 
above  are  called  liololiedral  forms,  from  the  Greek  for  all 
and  face,  the  number  of  planes  being  all  that  full  symmetry 
requires.  The  cube  has  eight  similar  solid  angles — similar, 
that  is,  in  the  enclosing  planes  and  plane  angles.  Con- 


.26 


CRYSTALLOGRAPHY. 


sequently  the  law  of  full  symmetry  requires  that  all  should 
have  the  same  planes  and  the  same  number  of  planes  ;  and 
this  is  the  general  law  for  all  the  forms.  This  is  a  conse- 
quence of  the  equality  of  the  axes  and  their  rectangular  in- 
tersections. 

But  in  some  crystalline  forms  there  are  only  half  the 
number  of  planes  which  full  symmetry  requires.  In  Fig. 
39  a  cube  is  represented  with  an  octahedral  plane  on  half, 
that  is,  four,  of  the  solid  angles.  A  solid  angle  having  such 


40. 


41. 


42. 


a  plane  is  diagonally  opposite  to  one  without  it.  The  same 
form  is  represented  in  Fig.  40.  only  the  cubic  faces  are  the 
smallest ;  and  in  Fig.  41  the  simple  form  is  shown  which  is 
made  up  of  the  four  octahedral  planes.  It  is  a  tetrahedron 
or  regular  three-sided  pyramid.  If  the  octahedral  faces  of 
Fig.  39  had  been  on  the  other  four  of  the  solid  angles  of  the 
cube,  the  tetrahedron  made  of  those  planes  would  have 
been  that  of  Fig.  42  instead  of  Fig.  41. 

Other  hemihedral  forms  are  represented  in  Figs.  43  to 
45.  Fig.  43  is  a  hemihedral  form  of  the  trapezohedron,  Fig. 


4,  p.  18;  Fig.  44,  hemihedral  of  the  hexoctahedron,  Fig.  7,  or 
a  hemi-hexoctahedron;  and  Fig.  45  is  a  combination  of  the 
tetrahedron  (plane  1)  and  hemi-hexoctahedron. 

In  these  forms  Figs.  41-44,  no  face  has  another  parallel 
to  it ;  and  consequently  they  are  called  inclined  hemihe- 
drons. 

Fig.  46  represents  a  cube  with  the  planes  of  a  tetrahexa- 


ISOMETRIC    SYSTEM. 


hedron,  as  already  explained.  In  fig.  47,  the  cube  has 
only  one  of  the  planes  i-2  on  each  edge,  and  therefore  only 
twelve  in  all ;  and  hence  it  affords  an  example  of  hemihe- 
drism — a  kind  that  is  presented  by  many  crystals  of  pyrite. 


Fig.  48  is  the  hemihedral  form  resulting  when  these  twelve 

planes  i-2  are  extended  to  the  obliteration  of  the  cubic 

faces ;  and  Fig.  49  is  another,  made  of  the 

other  twelve  of  these  planes.     Again,  in  Fig. 

50,  a  cube  is  represented  having  only  three 

out  of  the  six  planes  of  Fig.  22,  and  this  is 

another   example   of    hemihedrism.      These 

kinds  differ  from  the  inclined  hemihedrons 

in  having  opposite,  parallel  faces,  and  hence 

they  are  called  parallel  hemihedrons. 

4.  Internal  Structure  of  Isometric  Crystals,  or  Cleavage. 

— The  crystals  of  many  isometric  minerals  have  cleavage,  or 
a  greater  or  less  capability  of  division  in  directions  situated 
symmetrically  with  reference  to  the  axes.  The  cleavage 
directions  are  parallel  either  to  the  faces  of  the  cube,  the 
octahedron,  or  the  dodecahedron.  In  galenite  (p.  160) 
there  is  easy  cleavage  in  three  directions  parallel  to  the  faces 
of  the  cube  ;  in  fluorite  (p.  227),  in  four  directions  parallel 
to  the  faces  of  the  octahedron ;  in  sphalerite  (p.  170)^  in 
six  directions  parallel  to  the  faces  of  the  dodecahedron. 
These  cleavages  are  an  important  means  of  distinguishing 
the  species. 

The  three  cubic  cleavages  are  precisely  alike  in  the  ease 
with  which  cleavage  takes  place,  and  in  the  kinds  of  surface 
obtained ;  and  so  is  it  with  the  four  in  the  octahedral  direc- 
tions, and  the  six  in  the  dodecaHedral.  Occasionally  cleav- 
ages of  two  of  These  systems  occur  in  the  same  mineral ; 
that  is,  for  example,  parallel  both  to  the  faces  of  the  cube 
and  of  the  octahedron ;  but  when  .so,  those  of  one  system  are 


CRYSTALLOGRAPHY. 


much  more  distinct  than  those  of  the  other,  and  cleavage 
surfaces  in  the  two  directions  are  quite  unlike  as  to  smooth- 
ness and  lustre. 

5.  Irregularities  of  Isometric  Crystals. — A  cube  has  its 
faces  precisely  equal,  and  so  it  is  with  each  of  the  forms  rep- 
resented in  Figs.  SJ  to  7,  p.  18.  This  perfect  symmetry  is 
almost  never  found  in  actual  crystals. 


51. 


52. 


53. 


H 


H 


A  cubic  crystal  has  generally  the  form  of  a  square  prism 
(Fig.  51  a  stout  one,  Fig.  52  another  long  and  slender),  or  a 
rectangular  prism  (Fig.  53).  In  such  cases  the  crystal  may 
still  be  known  to  be  a  cube  ;  because,  if  so,  the  kind  of  sur- 

55.  " 


;£ace_  and  kind  of  lustre  pnjhe  six  faces  will  be  precisely 
alike :  and  if  f  nere  Is  cubic_cTeavage  it  will  bejjexactly 
equal  in  facility  in  three  "rectangular  directions ;  or  if  there 
is  cleavage  in  four,  or  six,  directions,  it  will  be  equal  in 


ISOMETRIC    SYSTEM.  29 

degree  in  the  four,  or  the  six,  directions,  and  have  mutual 
inclinations  corresponding  with  the  angles  of  the  octahedron 
or  dodecahedron ;  and  thus  the  crystal  will  show  that  it  is 
isometric  in  system. 

The  same  shortening  or  lengthening  of  the  crystal  often 
disguises  greatly  the  octahedron,  dodecahedron,  and  other 
forms.  This  is  Illustrated  in  the  following  figures  :  Fig.  54 
shows  the  form  of  the  regular  octahedron ;  55,  an  octahe- 
dron lengthened  horizontally ;  56,  one  shortened  parallel  to 
one  of  the  pairs  of  faces ;  57,  one  lengthened  parallel  to 
another  pair,  the  ultimate  result  of  which  obliterates  two 
of  the  faces,  and  places  an  acute  solid  angle  in  place  of 
each.  The  solid  is  then  six-sided,  and  has  rhombic  faces 
whose  plane  angles  are  120°  and  60°.  The  following  figures 


58. 


illustrate  corresponding  changes  in  the  dodecahedron  (Fig. 
58).  In  Fig.  59  the  dodecahedron  is  lengthened  vertically, 
making  a  square  prism  with  four-sided  pyramidal  termina- 
tions. In  60,  it  is  shortened  vertically.  In  61  the  dodeca- 
hedron is  lengthened  obliquely  in  the  direction  of  an  octa- 
hedral axis,  and  in  62  it  is  shortened  in  the  same  direction, 
making  six-sided  prisms  with  trihedral  terminations. 


30  CRYSTALLOGRAPHY. 

So  again  in  the  trapezohedron  there  are  equally  deceptive 
forms  arising  from  elongations  and  shortenings  in  the  same 
two  directions. 

These  distortions  change  the  relative  sizes  of  planes,, but 
not  the  values  of  angle_s.  In  crystals  of  the  several  forms" 
represented  in  Figs.  54  to  57,  the  inclinations  are  the  same 
as  in  the  regular  octahedron.  There  is  the  same  constancy 
of  angle  in  other  distorted  crystals. 

Occasionally,  as  in  the  diamond,  the  planes  of  crystals 
are  convex;  and  then,  of  course,  the  angles  will  differ  from 
the"true  angle.  It  is  important,  in  order  to  meet  the  diffi- 
culties in  the  way  of  recognizing  isometric  crystals,  to  have 
clearly  in  the  mind  the  precise  aspect  of  an  equilateral  tri- 
angle, which  is  the  shape  of  a  face  of  an  octahedron;  the 
form  of  the  rhombic  face  of  the  dodecahedron;  and  the 
form  of  the  trapezoidal  face  of  a  trapezohedron.  With 
these  distinctly  remembered,  isometric  crystalline  forms 
that  are  much  obscured  by  distortion,  or  which  show  only 
two  or  three  planes  of  the  whole  number,  will  often  be 
easily  recognized. 

Crystals  in  this  system,  as  well  as  in  the  others,  often 
have  their  facesjstrjated.,  or  else_jough  withjDoints.     This 
is  generally  owmgTxTa  tendencylhTKe  forming  crystal  to 
63  make  two  different  planes  at  the  same  time, 

or  rather  an  oscillation  between  the  condi- 
tion necessary  for  making  one  plane  and  that 
for  making  another.  Fig.  63  represents  a 
cube  of  pyrite  with  striated  faces.  As  the 
faces  of  a  cube  are  equal,  the  _striat ions,  are 
alike  on  all.  It  will  be  noted  that  the  stria- 
tions  of  adjoining  faces  are  at  right  angles  to  one  another. 
The  little  ridges  of  the  striated  surfaces  are  made  up  of 
planes  of  the  pentagonal  dodecahedron  (Fig.  49,  p.  27),  and 
they  arise  from  an  oscillation  in  the  crystallizing  conditions 
between  that  which,  if  acting  alone,  would  make  a  cube, 
and  that  which  would  make  this  hemihedral  dodecahedron. 
Again,  in  magnetite,  oscillations  between  the  octahedron 
and  dodecahedron  produce  the  striations  in  Fig.  64. 

Octahedral  crystals  of  fluorite  often  occur  with  the  faces 

made  up  of  evenly  projecting  solid  angles  of  a  cube,  giving 

them  rough  instead  of  polished  planes.     This  has  arisen 

from  oscillation  between  octahedral  and  cubic  conditions. 

In  some  cases  crystals  are  filled  out  only  along  the  diago- 


TETRAGONAL   SYSTEM.  31 

nal  planes.  Fig.  65  represents  a  crystal  of  common  salt 
of  this  kind,  having  pyramidal  depressions  in  place  of  the 
regular  faces.  Octahedrons  of  gold  sometimes  occur  with 

65. 


MAGNETITE.  COMMON  SALT. 

three-sided  pyramidal  depressions  in  place  of  the  octahedral 
faces.  Such  forms  sometimes  result  also  when  crystals  are 
eroded  by  any  cause. 

II.  TETRAGONAL  SYSTEM. 

1,  Descriptions  of  Forms. — In  this  system  (1)  the  axes 
cross  at  right  angles;  (2)  the  vertical  axis  is  either  longer 
or  shorter  than  the  lateral;  and  (3)  the  lateral  axes  are 
equal. 

The  following  figures  represent  some  of  the  crystalline 
forms.  They  are  very  often  attached  by  one  extremity  to 
the  supporting  rock  and  have  perfect  terminating  planes 
only  at  the  other.  Square  prisms,  with  or  without  pyra- 
midal terminations,  square  octahedrons,  eight-sided  prisms, 
eight-sided  pyramids,  and  especially  combinations  of  these, 
are  the  common  forms.  Since  the  lateral  axes  are  equal, 
the  four  lateral  planes  of  the  square  prisms  are  alike  in 
lustre  and  surface-markings.  For  the  same  reason  the 
symmetry  of  the  crystal  is  throughout  by  fours;  that  is, 
the  number  of  similar  pyramidal  planes  at  the  extremity  is 
either  four  or  eight;  and  they  show  that  they  are  similar 
by  being  exactly  alike  in  inclination  to  the  basal  plane  as 
well  as  alike  in  lustre. 

There  are  two  distinct  square  prisms.  In  one  (Fig.  10) 
the  axes  connect  the  centres  of  the  lateral  faces.  In  the 


32 


CRYSTALLOGRAPHY. 


other  (Fig.  12)  they  connect  the  centres  of  the  lateral  edges. 
In  Fig.  11  the  two  prisms  are  combined;  the  figure  shows 
that  the  planes  of  one  truncate  the  lateral  edges  of  the 


1. 


IDOCRASE. 


APOPHTLLITE. 
11.  12. 


15. 


other,  the  interfacial  angle  between  adjoining  planes  being 
135°.  Figs.  2,  3,  4,  7,  are  of  others  having  planes  of  both 
prisms.  In  Fig.  13  one  prism  is  represented  within  the 
other. 

Fig.  14  represents  an  eight-sided  prism,  and  Fig.  15  a 
combination    of    a    square  prism 

!t-*)   with   an   eight-sided    prism 
i-%).     Another  example  of  this  is 
shown  in  Fig.  4,  and  also  in  Fig.  9, 
the  planes  i-2  in  one,  and  i-3  in 
the  other. 

The  basal  plane  in  these  prisms 
is  an  independent  plane,  because 
the  vertical  axis  is  not  equal  to  the 


TETRAGONAL   SYSTEM. 


33 


lateral,  and  hence  it  almost  always  differs  in  lustre  and 
smoothness  from  the  lateral. 

Like  the  square  prisms,  the  square  octahedrons  are  in 
two  series,  one  set  (Fig.  16)  having  the  lateral  or  basal 
edges  parallel  to  the  lateral  axes,  and  these  axes  connecting 
the  centres  of  opposite  basal  edges,  and  the  other  (Fig.  17) 
having  them  diagonal  to  the  axes,  these  axes  connecting 
the  apices  of  the  opposite  solid  angles,  as  in  the  isometric 
octahedron.  There  may  be,  on  the  same  crystal,  faces  of 
several  octahedrons  of  these  two  series,  differing  in  having 
their  planes  inclined  at  different  angles  to  the  basal  plane. 

16.  17.  18.  19. 


In  Figs.  5  and  7  planes  of  one  of  these  pyramids  terminate 
the  prism,  and  in  Figs.  6  and  8  the  planes  of  two.  In  Figs. 
1  to  3  there  are  planes  of  the  same  octahedron,  but  com- 
bined with  the  basal  plane  0;  and  in  Fig.  4  there  are  planes 
of  two,  with  0.  In  Fig.  9  there  are  planes  of  the  same 
octahedron,  with  planes  of  a  square  prism  (i-i),  and  of  an 
eight-sided  prism  (i-2).  In  Fig.  18  there  is  the  prism  i-i 
combined  with  two  octahedrons,  and  the  basal  plane  0; 
and  in  19  the  planes  of  one  octahedron  with  the  prism  /. 
Fig.  20  represents  an  eight-sided  double  pyramid,  made 

21. 


of  equal  planes,  equally  inclined  to  the  base;  and  Fig.  21, 
the  same  planes  on  the  square  prism  i-i.     The  small  planes, 
3 


34  CRYSTALLOGRAPHY. 

in  pairs,  on  Fig.  8,  are  of  this  kind.  In  Fig.  22  the  small 
planes  3-3  of  Fig.  8  occur  alone,  without  planes  of  the  four- 
sided  pyramids,  and  therefore  make  the  eight-sided  pyra- 
mid, 3-3. 

The  solid  made  of  two  such  eight-sided  pyramids  placed 
base  to  base  has  the  largest  number  of  similar  planes 
possible  in  the  tetragonal  system,  while  the  largest  number 
in  the  isometric  system  (occurring  in  the  hexoctahedron) 
is  forty- eight. 

2,  Positions  of  the  planes  with  reference  to  the  Axes. — Let- 
tering of  planes.  In  the  prism  Fig.  10,  the  lateral  planes  are  parallel  to 
the  vertical  axis  and  to  one  lateral  axis,  and  meet  the  other  lateral  axis 
at  its  extremity.  The  expression  for  it  is  hence  (c  standing  for  the  vertical 
axis  and  a,  b  for  the  lateral)  ic  :  ib  :  \a,  i,  as  before,  standing  for  in- 

finitj^and  indicating  parallelism. 
23.  For  the  prism  of  Fig.  12,  the 

prismatic  planes  meet  the  two 
lateral  axes  at  their  extremities, 
and  are  parallel  to  the  vertical, 
and  hence  the  expression  for 
them  is  ic  :  Ib  :  la.  In  the  an- 
nexed figure  the  two  bisecting 
lines,  a  -a  and  b  -b,  represent  the 
lateral  axes;  the  line  st  stands 
for  a  section  of  a  lateral  plane  of 
the  first  of  these  prisms,  it  being 

parallel  to  one  lateral  axis  and  meeting  the  other  at  its  extremity, 
and  ab  for  that  of  the  second,  it  meeting  the  two  at  their  extremities. 
In  the  eight-sided  prisms  (Figs.  14,  15),  each  of  the  lateral  planes  is 
parallel  to  the  vertical  axis,  meets  one  of  the  lateral  axes  at  its  extrem 
ity,  and  would  meet  the  other  axis  if  it  were  prolonged  to  two  or  three 
or  more  times  its  length.  The  line  ao,  in  Fig.  23,  has  the  position  of 
one  of  the  eight  planes;  it  meets  the  axis  b  at  o,  or  twice  its  length 
from  the  centre;  and  hence  the  expression  for  it  would  be  ic  :  2b  :  \a, 
or,  since  b  =  a,  ic  :  2  :  1,  which  is  a  general  expression  for  each  of  the 
eight  planes.  Again,  ap  has  the  position  of  one  of  the  eight  planes  of 
another  such  prism;  and  since  Op  is  three  times  the  length  of  Ob,  the 
expression  for  the  plane  would  be  ic  :  3  :  1.  So  there  may  be  other 
eight-sided  prisms;  and,  putting  n  for  any  possible  ratio,  the  expres- 
sion ic  :  n  :  1  is  a  general  one  for  all  eight-sided  prisms  in  the  tetra- 
gonal system. 

A  plane  of  the  octahedron  of  Fig.  16  meets  one  lateral  axis  at  its 
extremity,  and  is  parallel  to  the  other,  and  it  meets  the  vertical  axis  c 
at  its  extremity;  its  expression  is  consequently  (dropping  the  letters  a 
and  b,  because  these  axes  are  equal)  Ic  :  i  :  1.  Other  octahedrons  in 
the  same  vertical  series  may  have  the  vertical  axis  longer  or  shorter 
than  axis  c;  that  is,  there  may  be  the  planes  2c  :  i  :  1,  Qc  :  i  :  1,  4c  :  i : 
1,  and  so  on;  or  {c  :  i  :  1,  ic  :  i  :  1,  and  so  on;  or,  using  m  for  any  co- 
efficient of  c,  the  expression  becomes  general,  me  :  i :  1.  When  w  =  0 
the  vertical  axis  is  zero,  and  the  plane  is  the  basal  plane  0  of  the 


TETRAGONAL   SYSTEM. 


35 


prism;  and  when  m  =  infinity,  the  plane  is  ic  :  i  :  1,  or  the  vertical 
plane  of  the  prism  in  the  same  series,  i-i,  Fig.  10. 

The  planes  of  the  octahedron  of  Fig.  17  meet  two  lateral  axes  at  their 
extremities,  and  the  vertical  at  its  extremity,  and  the  expression  for 
the  plane  is  hence  Ic  :  1  :  1.  Other  octahedrons  in  this  series  will  have 
the  general  expression-  we  :  1  :  1,  in  which  m  may  have  any  value,  not 
a  decimal,  greater  or  less  than  unity,  as  in  the  preceding  case.  When 
in  this  series  m  —  infinity,  the  plane  is  that  of  the  prism  ic  :  1  :  1,  or 
that  of  Fig.  12. 

In  the  case  of  the  double  eight-sided  pyramid  (Figs.  20,  21,  22),  the 
planes  meet  the  two  lateral  axes  at  unequal  distances  from  the  centre; 
and  also  meet  the  vertical  axis.  The  expression  may  be  2c  :  2  :  1,  4c  : 
2  :  1,  5c  :  3  :  1,  and  so  on;  or,  giving  it  a  general  form,  me  :  n  :  1. 

In  the  lettering  of  the  planes  on  figures  of  tetragonal  crystals,  the 
first  number  (as  in  the  isometric  and  all  the  other  systems)  is  the  co- 
efficient of  the  vertical  axis,  and  the  other  is  the  ratio  of  the  other  two, 
and  when  this  ratio  is  a  unit  it  is  omitted. 

The  expressions  and  the  lettering  for  the  planes  are  then  as  follows: 


Expressions. 
For  square  prisms  ...........  j  *;    *  ;  {  ;  \ 

For  eight-sided  prisms  ..........     ic  :  n  :  1 


For  octahedrons  ............  j  %' 

For  double  eight-sided  pyramids, 


me 


i :  1 
1:1 

n  : 1 


Lettering. 

i-n 
m-i 
m 
m-n 


24. 


The  symbols  are  written  without  a  hyphen  on  the  figures  of  crystals. 
On  Fig.  14,  the  plane  i-n  is  that  particular  i-n  in  which  n  =  2,  or 
i-2.  In  Fig.  21  the  planes  of  the  double  eight-sided  pyramid,  m-n,  have 
m  —  1  and  n  =  2  (the  expression  being  1:2:1),  and  hence  it  is  let- 
tered 1-2.  In  Fig.  8  and  in  Fig.  22  it  is  the  one  in  which  m  =  3  and 
n  =  3  (the  expression  being  3:3:  1),  and  hence  the  lettering  3-3. 

The  length  of  the  vertical  axis  c  may  be  calculated  as  follows,  pro- 
vided the  crystal  affords  the  required  angles: 

Suppose,  in  the  form  Fig.  18,  the  inclination  of  0  on  plane  \-i  to 
have  been  found  to  be  130°,  or  of  i-i  on  the  same  plane,  140°  (one  fol- 
lows from  the  other,  since  the  sum  of  the  two,  as  has  been 
explained,  is  necessarily  270C).  Subtracting  90°,  we  have 
40°  for  the  inclination  of  the  plane  on  the  vertical  axis  c, 
or  50°  for  the  same  on  the  lateral  axis  a,  or  the  basal 
section.  In  the  right-angled  triangle,  OBC,  the  angle 
OBC  equals  40°.  If  OC  be  taken  as  a  —  1,  then  BC  will 
be  the  length  of  the  vertical  axis  c\  and  its  value  may  be 
obtained  by  the  equation  cot  40°  =  BC,  or  tan  50°  =  BC. 

On  Fig.  18  there  is  a  second  octahedral  plane,  lettered 
\-it  and  it  might  be  asked,  Why  make  this  plane  i-i, 
instead  of  I-/?  The  determination  on  this  point  is 
more  or  less  arbitrary.  It  is  usual  to  assume  that 
plane  as  the  unit  plane  in  one  or  the  other  series  of 
octahedrons  (Fig.  16  or  Fig.  17)  which  is  of  most  common  occur- 
rence, 6r  that  which  will  give  the  simplest  symbols  to  the  crystalline 


36  CRYSTALLOGRAPHY. 

forms  of  a  species;  or  that  which  will  make  the  vertical  axis  nearest 
to  unity;  or  that  which  corresponds  to  a  cleavage  direction. 

The  value  of  the  vertical  axis  having  been  thus  determined  from  1-&, 
the  same  may  be  determined  in  like  manner  for  \-i  in  the  same  figure 
(Fig.  18).  The  result  would  be  a  value  just  half  that  of  BC.  Or  if 
there  were  a  plane  2-i,  the  value  obtained  would  be  twice  BC,  or  BD 
in  Fig.  24;  the  angle  ODO-\-9Q°  would  equal  the  inclination  of  0  on 
2-i.  So  for  other  planes  in  the  same  vertical  zone,  as  3-i,  4-&,  or  any 
plane  m-i. 

If  there  were  present  several  planes  of  the  series  m-i,  and  their  in- 
clinations  to  the  basal  plane  0  were  known,  then,  after  subtracting 
from  the  values  90°,  the  cotangents  of  the  angles  obtained,  or  the 
tangents  of  their  complements,  will  equal  m  in  each  case;  that  is,  the 
tangents  (or  cotangents)  will  vary  directly  with  the  value  of  m.  The 
logarithm  of  the  tangent  for  the  plane  1-tf,  added  to  the  logarithm  of 
2,  will  equal  the  logarithm  of  the  tangent  for  the  plane  2-2,  and  so  on. 

The  law  of  the  tangents  for  this  vertical  zone  m-i  holds  for  the  planes 
of  all  possible  vertical  zones  in  the  tetragonal  system.  Further,  if 
the  square  prism  were  laid  on  its  side  so  that  one  of  the  lateral  planes 
became  the  base,  and  if  zones  of  planes  are  present  on  it  that  are  ver- 
tical with  reference  to  this  assumed  base,  the  law  of  the  tangents  still 
holds,  with  only  this  difference  to  be  noted,  that  then  one  of  the  late- 
ral axes  is  the  vertical.  It  holds  also  for  the  orthorhombic  system,  no 
matter  which  of  the  diametral  planes  is  taken  for  the  base,  since  all 
the  axial  intersections  are  rectangular.  It  holds  for  the  monoclinic 
system  for  the  zone  of  planes  that  lies  between  the  axes  cand  b  and 
that  between  the  axes  a  and  b,  since  these  axes  meet  at  right  angles, 
but  not  for  that  between  c  and  a,  the  angle  of  intersection  here  being 
oblique.  It  holds  for  all  vertical  zones  in  the  hexagonal  system,  since 
the  basal  plane  in  this  system  is  at  right  angles  to  the  vertical  axis. 
But  it  is  of  no  use  in  the  triclinic  system,  in  which  all  the  axial  inter- 
sections are  oblique. 

The  value  of  the  vertical  axis  c  may  be  calculated  also  from  the  in- 
clination of  0  on  1,  or  of  /on  1.  See  Fig.  2,  and  compare  it  with  Fig. 
17.  If  the  angle  /on  1  equals  140°,  then,  after  subtracting  90°,  we 
have  50°  for  the  basal  angle  in  the  triangle  OCB,  Fig.  24  ;  or  for  half 
the  interfacial  angle  over  a  basal  edge— edge  Z—  in  Fig.  17.  The  value 
of  c  may  then  be  calculated  by  means  of  the  formula 

c  =  tan  \Z  y£, 

by  substituting  50°  for  \Z  and  working  the  equation. 
For  any  octahedron  in  the  series  m,  the  formula  is 

me  =  tan  \Z  v/| 

Z  being  the  angle  over  the  basal  edge  of  that  octahedron.  Ifm  =  2, 
then  c  =  £  (tan  \Z  y$).  Further,  m  =  (tan  IZ  |/i)-f-  c. 

The  interfacial  angle  over  the  terminal  edge  of  any  octahedron  m 
may  be  obtained,  if  the  value  of  c  is  known,  by  the  formulas 

me  =  cot  8  cos  s  =  cot  iX 

X  being  the  desired  angle  (Fig.  17).  The  same  for  any  octahedron  m-i 
may  be  calculated  from  the  formulas 


TETRAGONAL  SYSTEM.  37 

/ 

me  =  cot  «  cos  s  =cos  iYy2 

Y  being  the  desired  angle  (Fig.  16). 

For  other  methods  of  calculation  reference  may  be  made  to  the 
"  Text-book  of  Mineralogy,"  or  to  some  other  work  treating  of  mathe- 
matical crystallography. 

3.  Hemihedral  Forms. — Among  the  hemihedral  forms 
under  the  tetragonal  system  there  is  a  tetrahedron,,  called  a 
sphenoid  (Fig.  25  or  26),  and  also  forms  in  which  only  half 
of  the  sixteen  planes  of  the  double  eight-sided  pyramid,  or 
half  the  eight  planes  of  an  eight-sided  prism — those  alter- 


25.  26.  27. 


nate  in  position — are  present  (Figs.  27,  28).  In  Fig.  27  the 
absent  planes  are  those  of  half  the  pairs  of  planes;  and  in 
Fig.  28  they  include  one  of  each  of  the  pairs,  as  will  be  seen 
on  comparing  these  figures  with  Fig.  21. 

4.  Cleavage. — In  this  system  cleavage  may  occur  parallel 
to  the  sides  of  either  of  the  square  prisms;  parallel  to  the 
basal  plane;  parallel  to  the  faces  of  a  square  octahedron; 
or  in  two  of  these  directions  at  the  same  time.     Cleavage 
parallel  to  the  base  and  that  parallel  to  a  prism  are  never 
equal,  so  that  such  prisms  need  not  be  confounded  with 
distorted  cubes. 

5.  Irregularities  in   Crystals. — The  square  prisms   are 
very  often  rectangular  instead  of  square,  and  so  with  the 
octahedrons.     But,  as  elsewhere  among  crystals,  the  angles 
remain  constant.     When  forms  are  thus  distorted,  the  four 
prismatic  planes  will  have  like  lustre  and  surface  markings, 
and  thus  show  that  the  faces  are  normally  equal  and  tl^e 
lateral  axes  therefore  equal.     If  the  plane  truncating  the 
edge  of  a  prism  makes  an  angle  of  precisely  135°  with  the 
faces  of  the  prism,  this  is  proof  that  the  prism  is  square,  or 
that  the  lateral  axes  are  equal,  since  the  angle  between  a 
diagonal  of  a  square  and  one  of  its  sides  is  45°,  and  135°  is 
the  supplement  of  45°. 

6.  Distinctions. — The   tetragonal  prisms  have   the  base 


38 


CRYSTALLOGRAPHY. 


different  in  lustre  from  the  sides,  and  planes  on  the  basal 
edges  different  in  angle  from  those  on  the  lateral,  and  thus 
they  differ  from  isometric  forms.  The  lateral  edges  may 
be  truncated,  and  the  new  plane  will  have  an  angle  of  135° 
with  those  of  the  prism,  in  which  they  differ  from  ortho- 
rhombic  forms, while  like  isometric.  The  extremities  of  the 
prism,  if  it  have  any  planes  besides  the  basal,  will  have 
them  in  fours  or  eights,  each  of  the  four,  or  of  the  eight, 
inclined  to  the  base  at  the  same  angle.  When  there  is  any 
cleavage  parallel  to  the  vertical  axis,  it  is  alike  in  two  di- 
rections at  right  angles  with  one  another.  The  lateral 
planes  of  either  square  prism  are  alike  in  lustre  and  mark- 
ings. 

III.  ORTHORHOMBIC  SYSTEM. 

1.  Descriptions  of  Forms. — The  crystals  under  the  or- 
thorhombic  system  vary  from  rectangular  to  rhombic  prisms 
and  rhombic  octahedrons,  and  include  various  combinations 
of  such  forms.  Figs.  1  to  7  are  a  few  of  those  of  the  spe- 
cies barite,  and  Figs.  8  to  10  of  crystals  of  sulphur. 


BAKITE. 


SULPHUR. 


Fig.  11  represents  a  rectangular  prism  (diametral  prism), 
and  Fig.  12  a  rhombic  prism,  each  with  the  axes.  The 
axes  connect  the  centres  of  the  opposite  planes  in  the  for- 
mer; but  in  the  latter  the  lateral  axes  connect  the  centres 
of  the  opposite  edges.  Of  the  two  lateral  axes  the  longer 
is  called  the  macrodiagonal,  and  the  shorter  the  brachydi- 


OETHORHOMB1C    SYSTEM. 


39 


agonal.  The  vertical  section  containing  the  former  is  the 
macrodiagonal  section,  and  that  containing  the  latter,  the 
bracJiy  diagonal  section. 

In  the  rectangular  prism,  Fig.  11,  only  opposite  planes 
are  alike,  because  the  three  axes  are  unequal.  Of  these 
planes,  that  opposite  to  the  larger  lateral  axis  is  called  the 
macfopinacoid,  and  that  opposite  the  shorter  the  brachy- 
pinacoid  (from  the  Greek  for  long  and  short,,  and  a  word 
signifying  board  or  table).  Each  pair — that  is,  one  of  these 
planes  and  its  opposite — is  called  a  hemiprism. 

In  the  rhombic  prism,  Fig.  12,  the  four  lateral  planes 
are  similar  planes.  But  of  the  four  lateral  edges  of  the 


prism  two  are  obtuse  and  two  acute.  Fig.  13  represents  a 
combination  of  the  rectangular  and  rhombic  prisms,  and 
illustrates  the  relations  of  their  planes.  Other  rhombic 

Erisms  parallel  to  the  vertical  axis  occur,  differing  in  inter- 
icial  angles,  that  is,  in  the  ratio  of  the  lateral  axes. 

Besides  vertical  rhombic  prisms,  there  are  also  horizontal 
prisms  parallel  to  each  lateral  axis,  a  and  b.  In  Fig.  2  the 
narrow  planes  in  front  (lettered  %l)  are  planes  of  a  rhombic 
prism  parallel  to  the  longer  of  the  lateral  axes,  and  those 
to  the  right  (H)  are  planes  of  another  parallel  to  the  shorter 
lateral  axis.  In  Fig.  6  the  planes  are  those  of  these  two 
horizontal  prisms.  Such  prisms  are  called  also  domes,  be- 
cause they  have  the  form  of  the  roof  of  a  house  (domus  in 
Latin  meaning  house).  In  Fig.  3  these  same  two  domes 
occur,  and  also  the  planes  (lettered  /)  of  a  vertical  rhom- 
bic prism.  Of  these  domes  there  may  be  many,  both  in 
the  macrodiagonal  and  the  brachydiagonal  series,  differing 
in  angle  (or  in  ratio  of  the  two.  intersected  axes).  Those 
parallel  to  the  longer  lateral  axis,  or  the  macrodiagonal, 
are  called  macrodomes  ;  and  those  parallel  to  the  shorter, 
or  brachydiagonal,  are  called  bracliydomes. 

A  rhombic  octahedron,  lettered  i,  is  shown  in  Fig.  8;  a 
combination  of  two,  lettered  1  and  £,  in  Fig.  9;  and  a  com- 


iO  CRYSTALLOGRAPHY. 

bination  of  four,  lettered  1,  -J,  £,  -J-,  in  Fig.  10.  This  last 
figure  contains  also  the  planes  1,  or  those  of  a  vertical 
rhombic  prism;  the  planes  1-f,  or  those  of  a  dome  parallel 
to  the  longer  lateral  axis;  the  planes  l-i,  or  those  of  a  dome 
parallel  to  the  shorter  lateral  axis;  the  plane  0,  or  the  basal 
plane;  the  plane  i-i,  or  the  wbrachypinacoid;  and  also  a 
rhombic  octahedron  lettered  1-3. 

2.  Positions  of  Planes.     Lettering  of  Crystals. — The  nota- 
tion is,  in  a  general  way,  like  that  of  the  tetragonal  system,  but  with  dif- 
ferences made  necessary  by  the  inequality  of  the  lateral  axes.    The  let- 
ters for  the  three  are  written  c  :  5  :  a ;  6  being  the  longer  lateral  and  a  the 
shorter  lateral.  In  place  of  the  square  prism  of  the  tetragonal  system,  i-i, 
there  are  the  hemiprisms  i-l  and  i-i,  or_the  macropinacoid  and  brachy- 
pinacoid,  having  the  expressions  ic  :  ib  :  la<  and  ic :  l£:  id.     The  form 
Jis  the  rhombic  prism,  having  the  expression  ic  :  15  :  Id,  correspond- 
ing to  the  square  prism  /  in  the  tetragonal  system.     The  planes  i~n  or 
i-ft,  are  other  rhombic  vertical  prisms,  the  former  corresponding  to  ic  : 
rnh  :  \a,  the  other  to  ic  :  \bj  na.     If  n  =  2,  the  plane  is  lettered  either 
i-2  or  i£.     The  plane  l-#  has  the  expression  Ic :  15 :  M.     m-n  and 
m-n  comprise  all  possible  rhombic  prisms  and  octahedrons,  and  cor- 
respond to  the  expressions  me  :  rib  :  la  and  me  :  15  :  na.     When  m  = 
infinity  they  become  i-n  and  i-n,  or  expressions  for  vertical  rhombic 
prisms;  when  n  =  infinity  they  become  m-l  and  m-i,  or  expressions 
for  macrodomes  and  brachydomes. 

The  question  which  of  the  three  axes  should  be  taken  as  the  verti- 
cal axis  is  often  decided  by  reference  simply  to  mathematical  con- 
venience. Sometimes  the  crystals  are  prominently  prismatic  only  in 
one  direction,  as  in  topaz,  and  then  the  axis  in  this  direction  is  made 
the  vertical.  In  many  cases  a  cleavage  rhombic  prism,  when  there  is 
one,  is  made  the  vertical,  but  exceptions  to  this  are  numerous.  There 
is  also  no  general  rule  for  deciding  which  octahedron  should  be  taken 
for  the  unit  octahedron.  But  however  decided,  the  axial  relations  for 
the  planes  will  remain  essentially  the  same.  In  Fig.  10,  bad  the  plane 
lettered  |  been  made  the  plane  1,  then  the  series,  instead  of  being  as  it 
is  in  the  figure,  1,  i,  ^,  £,  would  have  been  2,  1,  f,  f ,  in  which  the 
mutual  axial  relations  are  the  same. 

The  relative  values  of  the  axes  in  the  orthorhpmbic  system  may  be 
calculated  in  the  same  way  as  that  of  the  vertical  axis  in  the  tetra- 
gonal system,  explained  on  page  35.  The  law  of  the  tangents,  as 
stated  on  page  36,  holds  for  this  system. 

3.  Hemlhedral  Forms. — Hemihedral  forms  are  not  com- 
mon in  this  system.     Some  of  those  so  considered  have 
been  proved  to  owe  the  apparent  hemihedrism  to  their 
being  of  the  monoclinic  system,  as  in  the  case  of  datolite 
and  two  species  of  the  chondrodite  group.     In  a  few  kinds, 
as,  for  example,  calamine,  one  extremity  of  a  crystal  differs 


MONOCLINIC   SYSTEM.  41 

in  its  planes  from  the  other.  Such  forms  are  termed  licmi- 
morphic,  from  the  Greek  for  half  and  fonn.  They  become 
polar  electric  when  heated,  that  is,  are  pyroelectric,  show- 
ing that  this  hemimorphism  i$  connected  with  polarity  in 
the  crystal. 

4.  Cleavage. — Cleavage  may  take  place  in  the  direction 
of  either  of  the  diametral  planes  (that  is,  either  face  of  the 
rectangular  prism) ;  but  it  will  be  different  in  facility  and 
in  the  surface  afforded  for  each.     In  anhydrite,  however, 
the  difference  is  very  small.     Cleavage  may  also  occur  in 
the  direction  of  the  planes  of  a  rhombic  prism,  either  alone 
or  in  connection  with  cleavage  in  other  directions.     It  also 
sometimes  occurs,  as  in  sulphur,  parallel  to  the  faces  of  a 
rhombic  octahedron. 

5.  Irregularities  in  Crystals. — The  crystals  almost  never 
correspond  in  their  diametral  dimensions  with  the  cal- 
culated axial  dimensions.     They  are  always  lengthened, 
widened,  shortened,  or  narrowed  abnormally,  but  without 
affecting  the  angles.     Examples  of  diversity  in  this  kind  of 
distortion  are  given  in  Figs.  1  to  7,  of  barite. 

6.  Distinctions. — In  the  orthorhombic  system  the  angle 
135°  does  not  occur,  because  the  three  axes  are  unequal. 
There  are  pyramids  of  four  similar  planes  in  the  system, 
but  never  of  eight ;  and  the  angles  over  the  terminal  edges 
of  the  pyramids  are  never  equal  as  they  are  in  the  tetra- 
gonal system.     The  rectangular  octahedron  of  the  ortho- 
rhombic  system  is  made  up  of  two  horizontal  prisms,  as 
shown  in  Fig.  6,  and  is  therefore  not  a  simple  form ;  and 
it  differs  from  the  octahedron  of  the  tetragonal  system  cor- 
responding to  it  (Fig.  16,  p.  33)  in  having  the  angles  over 
the  basal  edges  of  two  values. 


IV.   MONOCLINIC  SYSTEM. 

1.  Descriptions  of  Forms. — In  this  system  the  three  axes 
are  unequal,  as  in  the  orthorhombic  system;  but  one  of 
the  axial  intersections  is  oblique,  that  between  the  axis  a 
and  the  vertical  axis  c.  The  following  examples  of  its 
crystalline  forms,  Figs.  1  to  6,  show  the  effect  of  this  ob- 
liquity. On  account  of  it  the  front  or  back  planes  above 
and  below  the  middle  in  these  figures  differ,  and  the  ante- 


42 


CRYSTALLOGRAPHY. 


rior  and  posterior  prismatic  planes  are  unequally  inclined 
to  a  basal  plane. 


2. 


PYROXENE. 


HORNBLENDE. 


The  axes  and  their  relations  are  illustrated  in  Figs.  7  and 
Fio".  7  represents  an  oblique  rectangular  prism,  and 
S^an  oblique  rhombic.  The  former  is  the  diametral 
prism,  like  the  rectangular  of  the  orthorhombic  system. 
The  axes  connect  the  centres  of  the  opposite  faces,  and  the 
planes  are  of  three  distinct  kinds,  being  parallel  to  unlike 
axes  and  diametral  sections.  In  the  latter,  as  in  the  rhom- 
bic prism  of  the  orthorhombic  system,  the  lateral  axes  con- 
nect the  centres  of  the  opposite  sides.  Moreover,  this 
rhombic  prism  may  be  reduced  to  the  rectangular  by  the 
removal  of  its  edges  by  planes  parallel  to  the  lateral  axes. 

6. 


The  axis  a,  or  the  inclined  lateral  axis  (inclined  at  an 
oblique  angle  to  the  vertical  axis  c),  is  called  the  clinodiago- 


MONOCLINIC   SYSTEM. 


43 


7. 


nal ;  and  the  axis  b,  which  is  not  inclined,  the  ortliodiago- 
nal  (from  the  Greek  for  right,  or  rectangular).  The  ver- 
tical section  through  the  for- 
mer is  called  the  clinodiago- 
nal  section;  it  is  parallel  to 
the  plane  i-i  (Figs.  1-6). 
The  vertical  section  through 
the  latter  is  the  orthodiayo- 
nal  section ;  it  is  parallel  to 
planes  i-i.  Owing  to  the  ob- 
lique angle  between  a  and  c< 


planes  above  a  differ  in 


their  relations  to  the  axes  from  those  below,  and  hence 
comes  the  difference  in  the  angle  they  make  with  the  basal 
plane. 

The  halves  of  a  crystal  either  side  of  the  clinodiagonal 
section — the  vertical  section  through  a  and  c — are  alike  in 
all  planes  and  angles.  Another  important  fact  is  this  :  that 
the  plane  i-l,  or  that  parallel  to  the  clinodiagonal  section, 
is  at  right  angles  not  only  to  0  and  i-i,  but  to  all  planes  in 
the  zone  of  6  and  i-i ;  that  is,  in  the  clinodiagonal  zone ; 
and  this  is  a  consequence  of  the  right  angle  which  axis  b 
makes  with  both  axis  c  and  axis  a.  The  plane  i-i  is  called 
the  orthopinacoid,  it  being  parallel  to  the  orthodiagonal ; 
and  the  plane  i-l,  the  clinopinacoid,  it  being  parallel  to  the 
clinodiagonal. 

Vertical  rhombic  prisms  have  the  same  relations  to  the 
lateral  axes  as  in  the  orthorhombic  system.  Domes,  or 
horizontal  rhombic  prisms,  occur  in  the  orthodiagonal  zone, 
because  the  vertical  axis  c  and  the  orthodiagonal  b  make 
right  angles  with  one  another.  In  Fig.  6  the  planes  1-1, 
%-i,  belong  to  two  such  domes.  They  are  called  clinodomes, 
because  parallel  'to  the  clinodiagonal. 

In  the  clinodiagonal  zone,  on  the  contrary,  the  planes 
above  and  below  the  basal  plane  differ,  as  already  stated, 
and  hence  there  can  be  no  orthodomes  ;  they  are  heiuiortko- 
domcs.  Thus,  in  Fig.  6,  -£-/,  1-i  are  planes  of  hemiortho- 
domes  above  /-/,  and  —  -J-i  is  a  plane  of  anolher  of  different 
angle  below  i-i.  The  plane,  and  its  diagonally  opposite, 
make  the  hemiorthodome. 

The  octahedral  planes  above  the  plane  of  the  lateral  axes 
also  differ  from  those  below.  Thus,  in  Figs.  5  and  6,  the 
planes  1,  1  are,  in  their  inclinations,  different  planes  from 


44  CRYSTALLOGRAPHY. 

the  planes  —  1,  —  1 ;  so  in  all  cases.  Thus  there  can  be  no 
monoclinic  octahedrons — only  hemi- 
octahedrons.  An  oblique  octahe- 
dron is  made  up  of  two  sets  of 
planes ;  that  is,  planes  of  two  hemi- 
octahedrons.  Such  an  octahedron 
may  be  modelled  and  figured,  but 
it  will  consist  of  two  sets  of  planes  : 
one  set  including  the  two  above  the 
basal  section  in  front  and  their 
diagonally  opposites  behind  (Fig. 
9),  and  the  other  set  including  the  two  below  the  basal  sec- 
tion and  their  diagonally  opposites  (Fig.  10). 

A  hemioctahedron,  since  it  consists  of  only  four  planes, 
is  really  an  obliquely  placed  rhombic  prism,  and  very  fre- 
quently they  are  so  lengthened  as  to  be  actual  prisms. 

2.  Positions  of  Planes.    Lettering  of  Crystals. — On  account 
of  the  obliquity  of  the  crystals,  the  planes  above  and  below  the  basal 
section  require  a  distinguishing  mark  in  their  lettering,  as  well  as  in 
the  mathematical  expressions  for  them.     One  set  is  made  minus  and 
the  other  plus.     The  plus  sign  is  omitted  in  the  lettering.     In  Fig.  7 
there  are  above  the  basal  section  (or  above  i-i)  the  planes  l-»,  \-i,  1,  \. 
but  below  it,  —%-i,  — 1.     The  phis  planes  are  those  opposite  the  acute 
intersection  of  the  basal  and  orthodiagonal  sections,  and  the  minus 
those  opposite  the  obtuse.     No  signs  are  needed  for  planes  of  the 
clinodiagonal  section,  since  they  are  alike  both  above  and  below  the 
basal  section. 

The  distinction  of  longer  and  shorter  lateral  axis  is  not  available  in 
this  system,  since  cither  may  be  the  clinodiagonal.  The  distinction 
of  clinodiagonal  and  orthodiagonal  planes  is  indicated  by  a  grave 
accent  over  the  number  or  letters  referring  to  the  clinodiagonal.  The 
lettering  for  the  clinodomes  on  Fig.  6  is  1-i,  2-1 — the  1  (initial  of  infi- 
nite, with  the  accent)  signifying  parallelism  to  the  c^'/wdiagonal.  The 
hemioctahedrons,  1,  2,  etc.,  need  no  such  mark,  as  the  expression  for 
them  is  Ic  :  1&  :  Id,  2c  :  Ib  :  Id,  the  planes  having  a  unit  ratio  for  d 
and  b.  But  the  plane  2-3,  in  Fig.  5,  requires  it,  its  expression  being 
20  :  Ib  :  2a;  the  fact  that  the  last  2  refers  to  the  clinodiagonal  is 
indicated  by  the  accent.  If  it  referred  to  the  orthodiagonal,  that  is, 
if  the  expression  for  the  plane  were  2c  :  2b  :  Id,  it  would  be  written 
2-2  without  the  accent. 

3.  Cleavage. — Cleavage  may  be  basal,  or  parallel  to  either 
of  the  other  diametral  sections,  or  parallel  to  a  vertical 
rhombic  prism,  or  to  the  planes  of  a  hemioctahedron;  or 
to  the  planes  of  a  clinodome,  or  to  that  of  a  hemiortho- 
dome.      If  occurring  in  two  or  more  directions  in  any 


TRICLINIC   SYSTEM. 


45 


species  it  is  always  different  in  degree  in  each  different 
direction,  as  in  all  the  other  systems. 

4.  Irregularities. — Crystals  of  this  system  may  be  elon- 
gated abnormally  in  the  direction  of  either  axis,  and  any 
diagonal.  The  hemiorthodomes  may  be  in  aspect  the  bases 
of  prisms,  and  the  hemioctahedrons  the  sides  of  prisms. 
Which  plane  in  the  zone  of  hemiorthodomes  should  be 
made  the  base,  and  which  in  the  series  of  hemioctahedrons 
should  be  assumed  as  the  fundamental  prism  determining 
the  direction  of  the  vertical  axis,  is  often  decided  differ- 
ently by  different  crystallographers.  Convenience  of  math- 
ematical calculation  is  often  the  principal  point  referred  to 
in  order  to  reach  a  conclusion. 


V.  TRICLINIC  SYSTEM. 

1.  Descriptions  of  Forms. — In  the  triclinic  system  the 
three  axes  are  unequal  and  their  three  intersections  are 
oblique,  and  consequently  there  are  never  more  than  two 
planes  of  a  kind;  that  is,  planes  having  the  same  inclina- 
tions to  either  diametral  section.  The  following  are  exam- 
ples: 


1. 


AXINITE. 


ANORTHITE. 


AMBLYGONITls,. 


The  difference  in  angle  from  monoclinic  forms  is  often 
very  small.  This  is  true  in  the  Feldspar  family.  Fig.  2, 
of  the  feldspar  called  anorthite,  is  very  similar  in  general 
form  to  Fig.  4,  of  orthoclase,  which  is  monoclinic.  This 


46 


CRYSTALLOG  R A  PHY. 


is  still  more  strikingly  seen  on  comparing  Fig.  4  with  Fig. 
5  representing  a  crystal  of  oligoclase,  another  one  of  the 
triclinic  feldspars.  The  planes  on  the  two  are  the  same 


4. 


ORTHOCLASE. 


OLIGOCLASE. 


with  one  exception;  but  there  is  this  difference,  that  in 
orthoclase,  as  in  all  monoclinic  crystals,  the  angle  between 
the  planes  0  and  i-l  (the  two  directions  of  cleavage)  is  90°; 
and  in  oligoclase  and  other  triclinic  feldspars  it  is  3°  to 
6°  from  90°,  being  in  oligoclase  93°  50',  and  in  anorthite 
94°  10'.  This  difference  in  angle  involves  oblique  inter- 
sections between  the  axes  b  and  c,  and  c  and  a,  which  are 
rectangular  in  monoclinic  forms.  There  is  a  similarly 
close  relation  between  the  triclinic  form  of  rhodonite  and 
that  of  pyroxene,  and  a  resemblance  also  in  composition. 

The  diametral  prism  in  this  system  is  similar  to  Fig.  7 
on  page  43,  under  the  monoclinic  system,  but  differs  in 
having  the  planes  all  rhomboidal  instead  of  part  rectangu- 
lar. The  form  corresponding  to  the  oblique  rhombic  prism 
of  the  monoclinic  system  (Fig.  8,  p.  43)  also  has  rhom- 
boidal instead  of  rhombic  planes;  moreover,  the  two  pris- 
matic planes  have  unequal  inclinations  to  the  vertical  dia- 
metral section,  and  are  therefore  dissimilar  planes.  The 
prism,  consequently,  is  made  of  two  hemiprisms,  and  the 
JDasal  plane  is  another,  making  in  all  three  hemiprisms. 

2.  Cleavage, — Cleavage  takes  place  independently  in  dif- 
ferent diametral  or  diagonal  directions.  In  the  triclinic 
feldspars  it  conforms  to  the  directions  in  orthoclase,  with 
only  the  exception  arising  from  the  obliquity  above  ex- 
plained. 


-IT'J^HEXAGONAL   SECTION   OF   HEXAGONAL   SYSTEM.         47 


VI.  HEXAGONAL  SYSTEM. 

This  system  is  distinguished  from  the  others  by  the 
character  of  its  symmetry — the  number  of  planes  of  a  kind 
around  the  vertical  axis  being  a  multiple  of  3.  The  num- 
ber of  lateral  axes  is  hence  3.  It  is  related  to  the  tetra- 
gonal system  in  having  the  lateral  axes  at  right  angles  to 
the  vertical  and  equal,  and  is  hence  like  it  also  in  the  opti- 
cal characters  of  its  crystals.  Its  hexagonal  prismatic  form 
approaches  orthorhombic  crystals  in  the  obtuse  angle 
(120°)  of  the  prism,  some  orthorhombic  crystals  having  an 
angle  of  nearly  120°. 

Under  this  system  there  are  two  sections: 

1.  The  HEXAGONAL  SECTION,  in  which  the  number  of 
planes  of  a  kind  around  each  vertical  axis  above  or  below 
the  basal  section  is  6  or  12. 

2.  The  EHOMBOHEDBAL  SECTION,  in  which  the  number 
of  planes  of  a  kind  around  each  half  of  the  vertical  axis, . 
above  or  below  the  basal  section,  is  3  or  6;  and,  in  addition, 
the  planes  above  alternate  in  position  with  those  below. 
The  forms  are  mathematically  hemihedral  to  the  hexago- 
nal, but  not  so  in  their  real  nature. 

I.    HEXAGONAL   SECTION. 

1.  Description  of  Forms. — Figs.  1  to  3  represent  some  of 
1.  2.  3. 


12. 


MIMETITE. 


BERYL. 


12 


APATITE. 


the  forms  under  this  section.     Figs.  2  and  3  show  only  one 
extremity;  and  such  crystals  are  seldom  perfect  at  both. 


48 


CRYSTALLOGRAPHY. 


All  exhibit  well  the  symmetry  ~by  sixes  which  characterizes 
this  section  of  the  hexagonal  system. 


Prisms.  Under  this  system  there  are  two  hexagonal 
prisms  and  a  number  of  occurring  twelve-sided  prisms. 
Fig.  4  represents  one  of  the  hexagonal  prisms,  with  its 
axes — the  three  lateral  connecting  the  centres  of  the  oppo- 
site edges.  The  lateral  angles  of  the  prism  are  120°.  If 
the  lateral  edges  of  this  prism  are  truncated,  as  in  the  fig- 
ure of  apatite  (Fig.  3),  the  truncating  planes,  i-2,  are  the 
lateral  faces  of  another  similar  hexagonal  prism,  in  which, 
as  the  relations  of  the  two  show,  the  lateral  axes  connect 
the  centres  of  the  opposite  lateral  faces.  This  prism  is 
represented  in  Fig.  5. 

The  lateral  edges  of  the  hexagonal  prisms  occur  some- 
times with  two  similar  planes  on  each  edge,  and  these 
planes,  when  extended  to  the  obliteration  of  the  hexagonal 

prism,  make  a  twelve-sided  prism. 
These  two  planes  are  seen  in 
Fig.  8,  along  with  the  planes  1 
of  the  hexagonal  prism,  and  1  of 
a  double  six-sided  pyramid,  be- 
sides the  basal  plane  0. 

Double  pyramids.  The  double 
pyramids  are  of  three  kinds:  (1)  A  series  of  six-sided,  whose 
planes  belong  to  the  same  vertical  zone  with  the  planes  /. 
The  planes  of  two  such  pyramids  (lettered  1,  2)  are  shown 
in  Figs.  1  and  2,  three  of  them  in  Fig.  3  (lettered  -J-,  1,  2), 
and  one  in  Fig.  7,  and  one  such  double  pyramid,  without 
combination  with  other  planes,  in  Fig.  6.  (2)  A  series  of 
six-sided  double  pyramids  whose  planes  are  in  the  same 
vertical  zone  with  i-2,  examples  of  which  occur  on  Fig.  2 
(plane  2-2)  and  on  Fig.  3  (planes  1-2, 2-2,  4-2).  The  form  of 


TBTDYMITE. 


HEXAGONAL   SECTION   OF   HEXAGONAL   SYSTEM. 


49 


this  double  pyramid  is  like  that  represented  in  Fig.  6,  but 
the  lateral  axes  connect  the  centres  of  the  basal  edges.  The 
double  six-sided  pyramid  is  sometimes  called  a  quartzoid, 
because  it  occurs  in  quartz.  (3)  Twelve-sided  double  pyra- 
mids. Two  planes  of  such  a  pyramid  are  shown  on  a  hexa- 


9. 


gonal  prism  in  Fig.  9,  also  in  Fig.  2  (the  planes  3-f ),  and 
the  simple  form  consisting  of  such  planes  in  Fig.  10 — a 
form  called  a  lerylloid,  as  the  planes  are  common  in  beryl. 
In  Fig.  11  the  planes  1  belong  to  a  double  six-sided  pyra- 
mid ;  and  those  next  below  (of  which  three  are  lettered  W) 
to  a  double  twelve-sided  pyramid. 

2.  Lettering  of  Crystals.— The  prism  of  Fig.  5  is  lettered  «-2, 
because  it  is  parallel  to  the  vertical  axis,  and  has  the  ratio  of  1  :  2  be- 
tween two  lateral  axes.  This  is  shown  in  the  annexed  figure,  which 
represents  the  hexagonal  outline  of 
the  prism  i-2  circumscribing  that  of 
the  prism  /.  The  plane  i-  2  is  produced 
to  meet  axis  a,  which  it  does  when  a 
is  extended  to  twice  its  length;  whence 
the  ratio  for  the  axes  a,  a,  is  1  :  2. 

The  numbers  1,  2,  on  the  double 
hexagonal  pyramids  in  Fig.  1  indicate 
the  relative  lengths  of  the  vertical 
axis  of  the  two  pyramids,  they  having 
the  same  1  :  1  ratio  of  the  lateral  axes; 
and  so  in  Figs.  2,  3,  and  others. 

The  lettering  on  the  pyramids  of  the  other  series  in  Fig.  3,  1-2,  2-2, 
42,  indicates,  by  the  second  figure,  that  the  planes  .are  in  the  same 
vertical  zone  with  the  prismatic  plane  i-2,  and  by  the  first  figure  the 
relative  lengths  of  the  vertical  axes. 

In  the  twelve-sided  prisms  such  ratios  as  £-f ,  ££»  *-f  occur.    The 
fraction  in  any  case  expresses  the  ratio  of  the  lateral  axes  for  the  par- 
ticular planes.     The  double  twelve-sided  pyramids  have  the  ratios  3-£ 
4 


50 


CRYSTALLOGRAPHY. 


APATITE. 


(Fig.  2),  4-f,  and  others.  Both  in  these  forms  and  the  twelve  sided 
prisms,  the  second  iigure  in,  the  lettering,  expressing  the  ratio  of  the 
lateral  axes,  has  necessarily  a  value  between  1  and  2. 

3.  Hemihedral  Forms. — Fig.  13  represents  a  crystal  of 
apatite  in  which  there  are  two  sets  of  planes,  o  (=  3-f)  and 

o*  (—  4-f)  which  are  hemi- 
hedral, only  half  of  the  full 
number  of  each  o  existing,  in- 
stead of  all.  This  kind  of  hemi- 
hedrism  consists  in  the  suppres- 
sion of  an  alternate  half  of  the 
planes  in  each  pyramid  of  the 
double  twelve-sided'  pyramid 
(Fig.  10);  and  in  the  suppressed 
planes  of  the  upper  pyramid  be- 
ing here  directly  over  those  sup- 
pressed in  the  lower  pyramid. 
If  the  student  will  shade  over 
half  the  planes  alternately  of  the  two  pyramids  in  Fig.  10, 
putting  the  shaded  planes  above  directly  over  those  below, 
he  will  understand  the  nature  of  the  hemihedrism.  In 
some  hemihedral  forms  the  suppressed  planes  of  the  upper 
pyramid  alternate  with  those  of  the  lower;  but  -this  kind 
occurs  only  in  the  rhombohedral  section  of  the  hexagonal 
system. 

4.  Cleavage. — Cleavage  is  usually  basal,  or  parallel  to  a 
six-sided  pyramid.     Sometimes  there  are  traces  of  cleavage 
parallel  to  the  faces  of  a  six-sided  pyramid. 

5.  Irregularities  of  Crystals. — 
Distortions    sometimes    disguise 
greatly  the  real  forms  of  hexagonal 
crystals  by  enlarging  some  planes 
at  the  expense  of  others.     This  is 
illustrated  in  Fig.  14,  represent- 
ing the  actual  form  presented  by 
a  crystal  having  the  planes  shown 
in  Fig.  13.    "Whenever  in  a  prism 
the  prismatic  angle  is  exactly  120° 
or  150°,  the  form  is  almost  al- 
ways of  the  hexagonal  system. 


RHOMBOHEDRAL   SECTION   OF    HEXAGONAL   SYSTEM.       51 


2.    RHOMBOHEDRAL   SECTION". 

1.  Descriptions  of  Forms. — The  following  figures,,  1  to  17, 
represent  rhombohedral  crystals,  and  all  are  of  one  mineral, 
calcite.  They  show  that  the  planes  of  either  end  of  the 
crystal  are  in  threes,  or  multiples  of  threes,  and  that  those 
above  are  alternate  in  position  with  those  below.  There  is 


FIGURES  OF  CRYSTALS  OF  CALCITE. 

one  exception  to  this  remark,  that  of  the  horizontal  or  basal 
plane  0,  in  Figs.  8,  11,  13. 
The  simple  forms  include  : 

1.  Rhombohedrons,  Figs.   1  to  6.     These  forms  are  in- 
cluded under   six   equal  planes,  like  the  cube,  but  these 
planes  are  rhombic ;  and  instead  of  having  twelve  rectangu- 
lar edges,  they  have  six  obtuse  edges  and  six  acute. 

2.  Scalcnohedrons,    Fig.    7.     Scalenohedrons  are  really 
double  six-sided  pyramids ;  but  the  six  equal  faces  of  each 
extremity  of  the  crystals  are  scalene  triangles,  and  are  ar- 
ranged in  three  pairs ;  moreover,  the  pairs  above  alternate 
with  the  pairs  below ;  the  edges  in  which  the  pairs  above 
and  below  meet — that  is,  the  basal  edges — make  a  zigzag 
around  the  crystal. 

3.  Hexagonal  prisms,  /,  Fig.    8.      Regular   hexagonal 
prisms,  having  the  angle  between  adjoining  faces  120°. 

A  rhombohedron  has  two  of  its  solid  angles  made  up  of 


52  CRYSTALLOGRAPHY. 

three  equal  plane  angles.    When  in  position  the  apex  of  one 
of  these  solid  angles  is  directly  over  that  of  the  other,  as  in 


14. 


15. 


PIGUKES  OP  CRYSTALS  OP  CALCITE. 


Figs.  1  to  6,  and  also  in  Fig.  18,  and  the  line  connecting 
the  apices  of  these  angles  (Fig.  18)  is  called  the  vertical 
axis.  In  this  position  the  rhombohedron  has  six  terminal 


18. 


edges,  three  above  and  three  below,  and  six  lateral  edges. 
As  these  lateral  edges  are  symmetrically  situated  around  the 
centre  of  the  crystal,  the  three  lines  connecting  the  centres 
of  opposite  basal  edges  will  cross  at  angles  of  60°.  These 
lines  are  the  lateral  axes  of  the  rhombohedron,  and  they 
are  at  right  angles  to  the  vertical  axis.  It  is  stated  on  page 
45  that  rhombohedral  forms  are,  from  a  mathematical  point 
of  view,  Jiemiliedral  under  the  hexagonal  system.  The 
rhombohedron,  which  may  be  considered  a  double  three- 
sided  pyramid,  is  hemihedral  to  the  double  six-sided  pyra- 
mid. Fig.  19,  representing  the  latter  form,  has  its  alternate 
faces  shaded  ;  suppressing  the  faces  shaded,  the  form  would 
be  that  of  Fig.  18 ;  and  suppressing,  instead  of  these,  the 


RHOMBOHEDRAL   SECTION    OF   HEXAGONAL   SYSTEM.       53 


the 


faces  not  shaded,  the  form  would  be  that  of  another  rhom- 
bohedron, differing  only  in  position.  The  two  are  distin- 
guished as  plus  and  minus  rhombohedrons.  They  are  com- 
bined in  Figs.  20,  21,  forms  of  quartz.  Ehombohedrons 
vary  greatly  in  the  length  of  the  vertical  axis  with  reference 
to  the  lateral.  Figs.  1,  2,  3,  and  18  represent  crystals  with 
the  vertical  axis  short,  and  Figs.  4,  5,  6  others  with  a  long 
vertical  axis.  In  the  former  the.  angle  over  a  terminal 
edge  is  obtuse  or  over  90°,  and  that  over  a  lateral,  acute ; 
and  in  the  latter  the  reverse  is  the  case,  the  angle  over  the 
terminal  edges  being  less  than  90° ;  the  former  are  called 
obtuse  rhombohedrons,  and  the  latter  acute. 

The  cube  placed  on  one  solid  angle,  with  the  diagonal 
between  it  and  the  opposite  solid  angle  vertical,  is,  in  fact, 
a  rhombohedron  intermediate  between  obtuse  and  acute 
rhombohedrons,  or  one  of  90° — the  edges  that  are  the  ter- 
minal in  this  position,  and  those  that  are  the  lateral,  being 
alike  rectangular  edges.  Fig.  3  has  nearly  the  form  of  a 
cube  in  this  position. 

The  relation  of  one  series  of  scalenohedrons  to 
rhombohedron  is  illustrated  in  Fig.  22. 
This  figure  represents  a  rhombohedron 
with  the  lateral  edges  bevelled.  These 
bevelling  planes  are  those  of  a  scalenohe- 
dron,  and  the  outer  lines  of  the  same  fig- 
ure show  the  form  of  that  scalenohedron 
which  is  obtained  when  the  bevelment  is 
continued  to  the  obliteration  of  the  rhom- 
bohedral  planes.  Fig.  14  represents  this 
scalenohedron  with  the  rhombohedral 
planes  much  reduced  in  size.  Other  sca- 
lenohedrons result  when  the  terminal 
edges  are  bevelled,  and  still  others  from 
pairs  of  planes  on  the  angles  of  a  rhombo- 
hedron. 

The  scalenohedron    is    hemihedral  to 
the  twelve-sided  double  pyramid  (Fig.  23). 

In  the  hexagonal  system  the  three  ver- 
tical axial  planes  divide  the  space  about 
the  vertical  axis  into  six  sectors  (Fig.  12,  p.  50).     The 
twelve-sided  double  pyramid  has  in  each  pyramid  a  pair  of 
faces  for  each  sector;  that  is,  six  pairs  for  each  pyramid. 
If  now  the  three  alternate  of  these  pairs  in  the  lower  pyra- 


54  CRYSTALLOGRAPHY. 

mid,  and  those  in  the  upper  pyramid  alternate  with  these  (the 
shaded  in  Fig.  23),  were  enlarged  to  the  obliteration  of  the 
rest  of  the- planes,  the  resulting  form  would 
be  a  scalenohedron — a  solid  with  three 
pairs  of  planes  to  each  pyramid  instead  of 
six.  Such  is  the  mathematical  relation  of 
the  scalenohedron  to  the  twelve-sided 
double  pyramid.  If  the  faces  enlarged 
were  those  not  shaded  in  Fig.  23,  another 
scalenohedron  would  be  obtained  which 
would  be  the  minus  scalenohedron,  if  the 
other  were  designated  the  plus. 

Fig.  8  shows  the  relations  of  a  rhombo- 
hedron  to  a  hexagonal  prism.  The  planes  R  replace  three 
of  the  terminal  edges  at  each  base  of  the  prism,  and  those 
above  alternate  with  those  below.  The  extension  of  the 
planes  R  to  the  obliteration  of  those  of  the  prismatic 
planes,  /,  and  that  of  the  basal  plane  0,  would  produce  the 
rhombohedron  of  Fig.  1.  Figs.  9  and  10  represent  the 
same  prism,  but  with  terminations  made  by  the  rhombo- 
hedron of  Fig.  2. 

By  comparing  the  above  figures,  and  noting  that  the 
planes  of  similar  forms  are  lettered  alike,  the  combinations 
in  the  figures  will  be  understood.  Fig.  16  is  a  combination 
of  the  planes  of  the  fundamental  rhombohedron  R,  with 
those  of  another  rhombohedron  4,  and  of  two  scalenohedrons 
I3  and  I5.  Fig.  17  contains  the  planes  of  the  rhombohe- 
dron — J-,  with  those  of  the  scalenohedron  I3,  and  those  of 
the  prism  /.  These  figures,  and  Figs.  14,  22,  have  the 
fundamental  rhombohedron  revolved  60°  from  the  position 
in  Fig.  1,  so  that  two  planes  R  are  in  view  above  instead 
of  the  one  in  that  figure. 

2.  Lettering  of  Figures.— Figs.  1  to  6,  representing  rhombo- 
hedrons  of  the  species  calcite,  are  lettered  with  numerals,  excepting 
Fig  1.  In  Fig.  1  the  letter  R  stands  for  the  numeral  1,  and  the 
numerals  on  the  others  represent  the  relative  lengths  of  their  vertical 
axes,  the  lateral  being  equal.  In  Fig.  4  the  vertical  axis  is  twice  that 
in  Fig.  1;  in  Fig.  6  thirteen  times;  and  in  Fig.  15  the  planes  lettered 
16  are  those  of  a  rhombohedron  whose  vertical  axis  is  sixteen  times 
that  of  Fig.  1.  The  rhornbohedrons  of  Figs.  1,  5,  6,  and  15  are  plus 
rhombohedrons;  that  is,  they  are  in  the  same  vertical  series;  while  2 
and  3  are  minus  rhombohedrons,  as  explained  above.  The  rhombo- 
hedron, when  its  vertical  axis  is  reduced  in  length  to  zero,  becomes 
the  single  basal  plane  lettered  0  in  the  series.  If,  on  the  contrary, 
the  vertical  axis  of  the  rhombohedron  is  lengthened  to  infinity,  the 


RHOMBOHEDRAL   SECTION"   OF   HEXAGONAL   SYSTEM.       55 


faces  of  the  rhombohedron  become  those  of  a  six-sided  prism.  This 
last  will  be  seen  from  the  relations  of  the  planes  R  to  /on  Fig.  8,  and 
from  the  approximation  to  a  prismatic  form  in  the  planes  16  of  Fig. 
15.  For  an  explanation  of  the  lettering  of  other  planes  on  rhombo- 
hedral crystals,  reference  must  be  made  to  the  "  Text-Book  of  Miner- 
alogy." 

3.  Hemihedrism.     Tetartohedrism. — Hemihedrism  occurs 
among  rhombohedral  forms,  similar  to  that  in  Fig.  13, 
page  50,  except  that  the  suppressed  planes  of  one  pyramid 
are   alternate   with  those   of  the   other. 

One  of  these  is  represented  in  Fig.  24. 
The  planes  6-f  are  six  in  number  at  each 
extremity,  and  are  so  situated  that  they 
give  a  spiral  aspect  to  the  crystal.  If 
these  planes  were  only  three  in  number 
at  each  extremity,  the  alternate  three  of 
the  six,  the  form  would  be  tetartohedral 
to  the  double  six-sided  pyramid  ;  that  is, 
there  would  be  one  fourth  the  number  of 
planes  that  exist  in  the  double  twelve- 
sided  pyramid,  or  6  planes  instead  of  24. 
Such  cases  of  hemihedrism  and  tetarto- 
hedrism  are  common  in  crystals  of  quartz, 
and  when  existing,  the  crystals  are  said 
to  be  plagihedral,  from  the  Greek  for  oblique  and/ace.  In 
some  crystals  the  spiral  turns  to  the  right  and  in  others  to 
the  left,  and  the  two  kinds  are  distinguished  as  right-handed 
and  left-handed.  There  are  also  tetartohedral  forms  in 
which  one  whole  pyramid  of  a  scalenohedron,  or  of  a  rhom- 
bohedron, is  wanting.  For  example,  in  crystals  of  tourma- 
line rhombohedral  planes,  and  sometimes  scalenohedral, 
may  occur  at  one  extremity  of  the  prism  and  be  absent 
from  the  other.  This  dissimilarity  in  the  two  extremities 
of  a  crystal  of  tourmaline  is  connected  with  pyro-electric 
polarity  in  the  mineral.  Three-sided  prisms,  hemihedral 
to  the  hexagonal  prism,  are  common  in  some  rhombohedral 
species,  as  tourmaline. 

4.  Cleavage. — Cleavage   usually  takes  place  parallel  to 
the  faces   of  a  rhombohedron,  as  in   calcite,  35. 
corundum.     Not  unfrequently  the  rhombohe- 
dral cleavage  is  wanting,  and  there  is  highly 

perfect  cleavage  parallel  to  the  basal  plane,  as 
in  graphite,  brucite. 

5.  Irregularities    of    Crystals. — Distortions 

occur  of  the  same  nature   with  those  under  the  other 


56 


CRYSTALLOGRAPHY. 


systems.  Some  examples  are  given  under  quartz.  Some 
rhombohedral  species,  as  dolomite,  have  the  opposite  faces 
convex  or  concave,  as  in  Fig.  25. 

Occasional  curved  crystals  occur,  as  in  Fig.  26,  repre- 
senting crystals  of  quartz,  and  Fig.  27  of  a  crystal  of  chlo- 


26. 


QUAKTZ. 


CHLOKITE. 


rite.     The  feathery  crystallizations  on  windows,  called  frost, 
are  examples  of  curved  forms  under  this  system. 


VII.  DISTINGUISHING  CHARACTERS  OF  THE  SEVERAL 
SYSTEMS  OF  CRYSTALLIZATION. 

1.  ISOMETRIC  SYSTEM. — (1)  There  may  be  symmetrical 
groups  of  4  and  8  similar  planes  about  the  extremities  of 
each  cubic  axis;  and  of  3  or  6  similar  planes  about  the  ex- 
tremities of  each  octahedral  axis>     (2)  Simple  holohedral 
forms  may  consist  of  6  (cube),  8  (octahedron),  12  (dodeca- 
hedron), 24  (trapezohedron,  trigonal  trisoctahedron,  and 
tetrahexahedron),  and  48  (hexoctahedron)  planes. 

2.  TETRAGONAL  SYSTEM. — (1)  Symmetrical  groups  of 
4  and  8  similar  planes  occur  about  the  extremities  of  the 
vertical  axis  only.     (2)  Prisms  occur  paralM  only  to  the 
vertical  axis;  and  these  prisms  are  either  square  or  eight- 
sided.     (3)  The  simple  holohedral  forms  may  consist  of  2 
planes  (the  bases),  of  4  planes  (square  prisms),  of  8  planes 
(eight-sided  prisms  and  square  octahedrons),  of  16  planes 
(double  eight-sided  pyramids). 

3.  PRTHORHOMBIC  SYSTEM. — (1)  Symmetrical  groups  of 
4  similar  planes  may  occur  about  the  extremities  of  either 
axis,  but  those  of  one  axis  may  be  referred  equally  to  the 
others.     (2)    The   prisms  are   rhombic  prisms  only,  and 
these  may  occur  parallel  to  either  of  the  axes,  the  horizon- 


TWIN,    OR   COMPOUND,    CRYSTALS.  57 

tal  as  well  as  the  vertical.  (3)  Simple  holohedral  forms 
may  consist  of  2  planes  (the  bases,  and  each  pair  of  dia- 
metral planes),  of  4  planes  (rhombic  prisms  in  the  three 
axial  directions),  and  of  8  planes  (the  rhombic  octahedrons). 
(4)  The  forms  may  be  divided  into  equal  halves,  symmet- 
rical in  planes,  along  each  of  the  diametral  sections. 

4.  MONOCLINIC  SYSTEM. — (1)  No  symmetrical  groups  of 
similar  planes  ever  occur  around  the  extremities  of  either 
axis.     (2)  The  prisms  are  rhombic  prisms,  and  these  can 
occur  parallel  only  to  the  vertical  axis  and  the  clinodiagonal. 
(3)  The   planes  occurring  in  vertical   sections  above  and 
below  the  basal  section,  either  in  front  or  behind,  are  all 
unlike  in  inclination  to  that  section,  excepting  the  pris- 
matic planes  in  the  orthodiagonal  zone.     (4)  Simple  forms 
consist  of  2  planes  (the  bases,  the  diametral  planes,  and 
hemiorthodomes),  of  4  planes  (rhombic  prisms  in  two  direc- 
tions and  hemioctahedrons).     (4)  The  forms  may  be  di- 
vided into  equal  and  similar  halves  only  along  the  clinodi- 
agonal section.     No  interfacial  angle  of  90°  occurs  except 
between  the  planes  of  the   clinodiagonal   zone  and  the 
clinopinacoid. 

5.  TRICLINIC  SYSTEM. — In  triclinic  crystals  there  are  no 
groups  of  similar  planes  which  include  more  than  2  planes, 
and  hence  the  simple  forms  consist  of  2  planes  only.     The 
forms   are  not  divisible  into  halves  having  symmetrical 
planes.     There  are  no  interfacial  angles  of  90°. 

6.  HEXAGONAL  SYSTEM. — Symmetrical  groups  of  3,  6, 
and  12  similar  planes  may  occur  about  the  extremities  of 
the  vertical  axis.     (2)  Prisms  occur  parallel  to  the  vertical 
axis,  and  are  either  six-  or  twelve-sided  (3  in  a  hemihedral 
form)  and  equilateral.     (3)  Simple  holohedral  forms  may 
consist  of  2  planes  (the  basal),  of  6  planes  (hexagonal  prism), 
of  12  planes  (twelve-sided  prisms  and  double  six-sided  pyra- 
mids), of  24  planes  (double  twelve-sided  pyramids).    Simple 
rhombohedral  forms  may  consist  of  2  planes  (the  basal),  of  6 
planes  (rhombohedrons),  and  of  12  planes  (scalenohedrons). 

The  distinguishing    optical    characters  are    mentioned 
beyond. 

2.  TWIN,  OR  COMPOUND,  CRYSTALS. 

Compound  crystals  consist  of  two  or  more  single  crystals, 
united  usually  parallel  to  an  axial  or  diagonal  section.    A  few 


58 


CRYSTALLOGRAPHY. 


are  represented  in  the  following  figures.  Fig.  1  represents 
a  crystal  of  snow  of  not  unfrequent  occurrence.  As  is  evi- 
dent to  the  eye,  it  consists  either  of  six  crystals  meeting  in 
a  point,  or  of  three  crystals  crossing  one  another ;  and,  be- 
sides, there  are  numerous  minute  crystals  regularly  arranged 
along  the  rays.  Fig.  2  represents  a  cross  (cruciform)  crys- 


1. 


5. 


6. 


tal  of  staurolite,  which  is  similarly  compound,  but  made  up 
of  two  intersecting  crystals.  Fig.  3  is  a  compound  crystal 
of  gypsum,  and  Fig.  4  one  of  spinel.  These  will  be  under- 
stood from  the  following  figures. 

Fig.  5  is  a  simple  crystal  of  gypsum ;  if  it  be  bisected 
along  ab,  and  the  right  half  be 
inverted  and  applied  to  the  other, 
it  will  form  Fig.  3,  which  is  there- 
fore a  twin  crystal  in  which  one 
half  has  a  reverse  position  from 
the  other.  Fig.  6  is  a  simple  oc- 
tahedron ;  if  it  be  bisected  along 
the  plane  abcde,  and  the  upper 
half,  after  being  revolved  half 
way  round,  be  then  united  to  the 
lower,  it  will  have  the  form  of  Fig.  4.  Both  of  these, 
therefore,  are  similar  twins,  in  which  one  of  the  two  com- 
ponent parts  is  reversed  in  position. 

Crystals  like  Figs.  3  and  4  have  proceeded  from  a  com- 
pound nucleus  in  which  one  of  the  two  molecules  was  re- 
versed ;  and  those  like  Fig.  1,  from  a  nucleus  of  three  (or 
six)  molecules.  Compound  crystals  of  the  kinds  above  de- 
scribed thus  differ  from  simple  crystals  in  having  been 
formed  from  a  nucleus  of  two  or  more  united  molecules, 
instead  of  from  a  simple  nucleus. 

Compound  crystals  are  generally  distinguished  by  their 
re-entering  angles,  and  often  also  by  the  meeting  of  striae 


T\VIX,    OR   COMPOUND,    CRYSTALS. 


59 


at  an  angle  along  a  line  on -a  surface  of  a  crystal,  the  line 
indicating  the  plane  of  junction  of  the  two  crystals. 

Compound  crystals  are  called  twolings,  trillings,  foil  rlings, 
according  as  they  consist  of  two,  three,  or  four  united  crys- 
tals. Fig.  1  represents  a  trilling,  and  2,  3,  and  4,  twolings. 
In  3  and  4  the  combined  crystals  are  simply  in  contact 
along  the  plane  of  junction ;  in  2  they  cross  one  another ; 
the  former  are  called  contact-twins  and  the  latter  penetra- 
tion-twins. 

Besides  the  above,  there  are  also  geniculated  crystals,  as 
in  the  annexed  figure  of  a  crystal  of  rutile.  The  bending 
has  here  taken  place  at  equal  distances  from  the  centre  of 
the  crystal,  and  it  must  therefore  have  been  subsequent  in 
time  to  the  commencement  of  the  crystal. 
The  prism  began  from  a  simple  molecule  ; 
but  after  attaining  a  certain  length  an  ab- 
rupt change  of  direction  took  place.  The 
angle  of  geniculation  is  constant  in  the 
same  mineral  species,  for  the  same  reason 
that  the  interfacial  angles  of  planes  are 
fixed ;  and  it  is  such  that  a  cross-section 
directly  through  the  geniculation  is  parallel  to  the  position 
of  a  common  secondary  plane.  In  the  figure  given,  the 
plane  of  geniculation  is  parallel  to  one  of  the  terminal 
edges.  In  rutile  the  geniculated  crystals  sometimes  repeat 
the  bendings  at  each  end  until  the  extremities  meet  to  form 
a  wheel-like  twin. 

In  some  species,  as  albite,  the  reversion  of  position  on 
which  this  kind  of  twin  depends,  takes  place  at  so  short  in- 
tervals that  the  crystal  consists  of 
8.  parallel  plates,  each  plate  often 

less  than  a  twentieth  of  an  inch 
in  thickness.  A  section  of  such 
a  crystal,  made  transverse  to  the 
plate,  is  given  in  Fig.  8  ;  without 
the  twinning  the  section  would 
have  been  as  in  Fig.  9.  The 
plates,  as  the  figure  shows,  make 
with  one  another  at  their  edges  a 
re-entering  angle  (in  albite  an 
angle  of  172°  48'),  and  hence  a 

plane  of  the  albite  crystal  at  right  angles  to  the  twinning 
direction,  is  covered  with  a  series  of  ridges  and  depressions 


60 


CRYSTALLOGRAPHY. 


which  are  so  minute  as  to  be  only  fine  striations,  sometimes 
requiring  a  magnifying  power  to  distinguish.  Such  stria- 
tions  in  albite  are  therefore  an  indication  of  the  compound 
structure. 

This  kind  of  twinning  is  sometimes  called  polysynthetic 
twinning.     It  occurs  in  all  the  triclinic  feldspars,  and  is  a 
means  of  distinguishing  them  from  orthoclase.     Similar 
twinning  occurs  also  in  calcite,  and  some  other  species. 
In  "some  twin  crystals  the  two  component  parts  of  the 
crystal  are    not  united  by  an  even 
plane,  but  run  into  one  another  with 
great  irregularity.     Oases  of  this  kind 
occur  in  the  species  quartz  in  twins 
made  up  of  the  forms  R  and  —  R  (or 

—  1).     In  Fig.  10  the  shaded  parts  of 
the  pyramidal  planes  are  of  the  form 

—  1,  and  the  non-shaded  parts  of  R. 
Each  of  the  faces  is  made  up  partly  of 
R  and  partly  of  — 1.     The  limits  of 
the  two  are  easily  seen  on  holding  the 
crystal  up  to  the  light,  since  the  —  1 
portion  is  less  well  polished  than  the 
other.     In  this    crystal,   as  in  other 
crystals   of  quartz,   the   striations  of 

planes  i  are  owing  to  oscillations  between  pyramidal  and 
prismatic  planes  while  the  formation  of  the  latter  was  in 
progress. 

The  compound  or  twinned  condition,  while  often  origi- 
nating in  a  compound  nucleus,  and  in  external  molecular 
influences,  may  also  be  produced  in  many  species  by  pres- 
sure or  a  blow. 

In  this  way  a  simple  rhombohedron  of  calcite  may  be 
made  a  true  twin  crystal,  or  a  polysynthetic  twin.  The 
grains  in  a  white  crystalline  limestone  or  marble — the  spe- 
cies calcite  or  dolomite — are  rhombohedral  in  cleavage,  like 
the  ordinary  crystals  of  these  minerals;  but  the  cleavage 
surfaces  are  usually  striated  parallel  to  the  longer  diameter 
of  the  rhombohedral  faces,  and  this  striation  is  due  to 
polysynthetic  twinning.  It  may  be  always  a  result  of  pres- 
sure at  the  time  of  the  crystallization  of  the  limestone. 
The  striations  common  in  the  triclinic  feldspars  have  been 
attributed  to  the  same  cause. 


PARAMORPHS.   PSEUDOMORPHS.  61 


3.  PARAMORPHS.  PARAMORPHISM. 

Many  examples  exist  in  which  elements,  and  compounds 
that  have  the  same  composition  essentially,  differ  in  crys- 
talline form  as  well  as  other  physical  qualities.  These  are 
examples  of  paramorphism.  Among  the  elements,  one 
marked  example  is  carbon,  which  is  isometric  in  the 
diamond,  but  hexagonal  in  graphite:  of  extreme  hardness, 
adamantine  lustre,  and  a  specific  gravity  of  3*53  in  the 
former;  of  extreme  softness,  a  metallic  lustre,  and  a  spe- 
cific gravity  of  2*1  in  the  latter.  Such  differences  may  be 
conceived  of  as  due  to  differences  in  molecular  condensa- 
tion. The  following  are  examples  among  compounds: 
Calcium  carbonate  occurs  rhombohedral  (and  G.  =  2 '72)  in 
calcite,  orthorhombic  (and  G.  =2*93)  in*  aragonite.  Silica 
is  rhombohedral  (the  hemihedral  section  of  the  hex- 
agonal system)  (and  G.  =  2*65)  in  quartz;  true  hexagonal 
(G.  =  2-29}  in  tridymite;  and  uncrystallizable  in  opal 
(G.  =  2-17).  Titanium  dioxide  has  an  orthorhombic  form 
in  brookite,  one  tetragonal  form  in  rutile,  and  another 
tetragonal  in  octahedrite.  In  the  hornblende  group, 
hornblende  and  pyroxene  are  alike  in  composition  and  in 
monoclinic  crystallization;  but  the  former  has  a  cleavage 
angle  of  124°  30',  .and  the  latter  of  87°  5'.  In  addition, 
other  species  of  the  group  having  these  two  cleavage  an- 
gles, as  anthophyllite  and  enstatite,  are  orthorhombic  in 
crystallization. 

In  general  one  of  the  forms  is  less  stable  under  the  or- 
dinary temperature  or  conditions  than  the  other,  because 
it  requires  for  formation  a  higher  temperature  or  some 
other  unusual  condition.  Thus  pyroxene  is  less  stable  than 
hornblende;  aragonite  than  calcite,  brookite  than  rutile. 

4.  PSEUDOMORPHS,  PSEUDOMORPHISM. 

The  crystalline  forms  under  which  a  species  occurs  are 
sometimes  those  of  another  species.  Quartz  often  has  the 
crystalline  form  of  calcite,  owing  to  a  substitution  of  silica 
for  the  calcium  carbonate  of  the  calcite  crystal.  Serpen- 
tine has  often  the  form  of  chrysolite,  chondrodite,  or  some 
other  magnesium  mineral,  owing  to  a  change  in  these  other 
magnesium  silicates  into  the  hydrous  magnesium  silicate 


CRYSTALLOGRAPHY. 


called  serpentine.'  Such  false  forms  are  called  ptcudo- 
morphsy  from  the  Greek  pseudos,  false,  and  morpTie,  form. 
The  same  process  that  turned  the  calcite  into  quartz  has 
converted  wood,,  shells,  and  corals  into  quartz;  in  other 
words,  made  silicified  wood,  shells,  and  corals. 

The  different  kinds  of  pseudomorphism  are  the  following: 

1.  By  substitution:  as   in    the    substitution   of    silica 
(quartz)  for  the  calcite. 

2.  By  chemical  alteration :  as  in  the  change  to  serpen- 
tine above  explained;  or  the  change  of  iron  carbonate  (sid- 
erite)  to  the  hydrous  iron  oxide  (limonite). 

3.  By  impression :  as  in  deposition  in  a  cavity  once  occu- 
pied by  a  crystal;  or  against  the  exterior  of  a  crystal. 

4.  By   paramorphism :    as     when     pyroxene    becomes 
changed  to  hornblende,  or  aragonite  to  calcite.     In  this  al- 
teration of  pyroxene,  as  fast  as  the  outer  part   becomes 
changed,  it    has    cleavage    parallel     to    the    hornblende 
prism  (/A/=  124°  30"),  instead  of  that  of  pyroxene  (87° 

5'),  as  in  the  accompanying  figure, 
which  in  its  central  part  repre- 
sents a  transverse  section  of  a 
crystal,  the  centre  pyroxene,  the 
outer  part  hornblende,  and  in  the 
upper  corner  a  longitudinal  section 
of  a  similarly  altered  pyroxene. 
The  cleavage-lines  are  often  an 
indication  of  its  progress.  Such 
hornblende  has  been  called  uralite, 
because  first  observed  (by  H.  Rose) 
Urals;  but  it  is  essentially  like  ordinary 


the 


in  a  rock  of 

hornblende.  In  the  figure  the  black  spots  represent  grains 
of  magnetite.  In  many  cases  no  change  in  composition 
attends  the  change;  but  in  others  there  are  some  replace- 
ments by  which  the  elimination  of  unessential  ingredients 
takes  place.  Iron  is  apt  to  be  this  removed  ingredient,  as 
it  is  in  many  of  the  methods  of  chemical  alteration;  and, 
consequently,  while  it  remains  in  the  crystal  it  takes  an 
independent  form,  and  usually  that  of  minute  grains  or 
crystals  of  magnetite,  or  hematite,  or  menaccanite. 


CRYSTALLINE    AGGREGATES. 


63 


5.  CRYSTALLINE  AGGREGATES. 

The  crystalline  aggregates  here  included  are  the  simple, 
not  the  mixed;  that  is,  they  are  those  consisting  of  crys- 
talline individuals  of  a  single  species. 

The  crystalline  individuals  may  be  (1)  distinct  crystals; 
(2)  fibres  or  columns;  (3)  scales  or  lamellae;  or  (4)  grains, 
either  cleavable  or  not  so. 

1.  Consisting  of  distinct  crystals. — The  distinct  crystal 
may  be  either  long  or  short  prismatic,  stout  or  slender  to 
acicular  (needle-like),  and  capillary  (hair-like);  or  they 
may  have  any  other  forms  of  crystals.  They  may  be  ag- 
gregated (a)  in  lines;  (b)  promiscuously  with  open  spaces; 
(c)  over  broad  surfaces;  (d)  about  centres.  The  various 
kinds  of  aggregates  thus  made  are: 

a.  Filiform. — Thread-like  lines  of  crystals,  the  crystals 
often  not  well  defined. 

b.  Dendritic. — Arborescent  slender  spreading  branches, 
somewhat  plant-like,  made  up  of  more  or  less  distinct  crys- 
tals, as  in  the  frost  on  windows,  and  in  arborescent  forms 
of  native  copper,  silver,  gold,  etc. 

Fig.  11  represents,  much  magnified,  an  arborescent  form 
of  magnetite  occurring  in  mica  at  Pennsbury,  in  Pennsyl- 
vania. Arborescent  delineations  over  surfaces  of  rock  are 
usually  called  dendrites.  They  have  been  formed  by  crys- 
tallization from  a  solution 
of  mineral  matter  which 
has  entered  by  some  crack 
and  spread  between  the 
layers  of  the  rock.  They 
are  often  black,  and  consist 
of  oxide  of  manganese; 
others,  of  a  brownish  color, 
are  made  of  limonite; 
others,  of  a  reddish  black 
or  black  color,  of  hematite. 
Moss-like  forms  also  occur, 
as  in  moss  agate. 

c.  Reticulated. — Slender          '  ^ 
prismatic   crystals    promis- 
cuously crossing,  with  open  spacings. 

d.  Divergent. — Free  crystals  radiating  from  a  central 
point. 


64  CRYSTALLOGRAPHY. 

e.  Drusy. — A  surface  is  drusy  when  covered  with  im- 
planted crystals  of  small  size. 

2.  Consisting  of  columnar  individuals. 

a.   Columnar9  when  the  columnar  individuals  are  stout. 
I.  Fibrous,  when  they  are  slender. 

c.  Parallel  fibres,  when  the  fibres  are  parallel. 

d.  Radiated)  when  the  columns  or  fibres  radiate  from 
centres. 

e.  Stellated,  when  the  radiations  from  a  centre  are  equal 
around,  so  as  to  make  star-like  or  circularly-radiated  groups. 

/.  Globular,  when  the  radiated  individuals  make  globu- 
lar or  hemispherical  forms,  as  in  wavellite. 

ff.  Botryoidalf  when  the  globular  forms  are  in  groups,  a 
little  like  a  bunch  of  grapes.  The  word  is  from  the  Greek 
for  a  bunch  of  grapes. 

h.  Mammillary,  having  a  surface  made  up  of  low  and 
broad  prominences.  The  term  is  from  the  Latin  mammil- 
la, a  little  teat. 

i.  Coralloidal,  when  in  open-spaced  groupings  of  slender 
stems,  looking  like  a  delicate  coral.  A  result  of  successive 
additions  at  the  extremity  of  a  prominence,  lengthening  it 
into  cylinders,  the  stems  generally  having  a  faintly  radi- 
ated structure. 

Specimens  of  all  these  varieties  of  columnar  structure, 
excepting  the  last,  often  have  a  drusy  surface,  the  fibres  or 
columns  ending  in  projecting  crystals. 

3.  Consisting  of  scales  or  lamellm. 

a.  Plumose,  having  a  divergent  arrangement  of  scales,  as 
seen  on  a  surface  of  fracture;  e.g.,  plumose  mica. 

b.  Lamellar,  tabular,  consisting  of  flat  lamellar  crystal- 
line individuals,  superimposed  and  adhering. 

c.  Micaceous,  having  a  thin  fissile  character,  due  to  the 
aggregation  of  scales  of  a  mineral  which,  like  mica,  has  emi- 
inent  cleavage. 

d.  Septate,  consisting  of  openly-spaced  intersecting  tabu- 
lar individuals;   also  divided  into  polygonal  portions  by 
reticulating  veins  or  plates.     A  septarium  is  a  concretion, 
usually  flattened  spheroidal  in  shape,  the  solid  interior  of 
which  is  intersected  by  partitions;  these  partitions  are  the 
fillings  of  cracks  in  the  interior  that  were  due  to  contraction 
on  drying.    Such  septate  concretions,  especially  when  worn 
off  at  surface,  often  have  the  appearance  of  a  turtle's  back, 
and  are  sometimes  taken  for  petrified  turtles. 


CRYSTALLINE    AGGREGATES.  65 

4.  Consisting  of  grains.     Granular  structure. — A  mas- 
sive mineral  may  be  coarsely  granular  or  finely  granular, 
as  in  varieties  of  marble,  granular  quartz,  etc.     It  is  termed 
saccharoidal  when  evenly  granular,  like  loaf-sugar.     It  may 
also  be  cryptocrystalline,  that  is,  having  no  distinct  grains 
that  can  be  detected  by  the  unaided  eye,  as  in  flint.     The 
term  cryptocrystalline  is  from  the  Greek  for  concealed  crys- 
talline.    Aphanitic,  from  the  Greek  for  invisible,  has  the 
same  signification.     The  term  ceroid  is  applied  when  this 
texture  is  connected  with  a  waxy  lustre,  as  in  some  common 
opal. 

Under  this  section  occur  also  globular,  botryoidal,  and 
mmntnillary  forms,  as  a  result  of"  concretionary  action  in 
which  no  distinct  columnar  interior  structure  is  produced. 
They  are  called  pisolitic  when  in  masses  consisting  of  grains 
as  large  as  peas  (from  the  Latin  pisum,  a  pea),  and  oolitic 
when  the  grains  are  not  larger  than  the  roe  of  a  fish,  from 
the  Greek  for  egg. 

5.  Forms  depending  on  mode  of  deposition. — Besides  the 
above,  there  are  the  following  varieties  which  have  come 
from  mode  of  deposition: 

a.  Stalactitic,  having  the  form  of  a  cylinder,  or  cone, 
hanging  from  the  roofs  of  cavities  or  caves.     The  term 
stalactite  is  usually  restricted  to  the  cylinders  of  calcium 
carbonate   hanging  from  the  roofs  of  caverns;  but  other 
minerals  are  said  to  have  a  stalactitic  form  when  resembling 
these  in  their  general  shape  and  origin.     Chalcedony  and 
limonite  are  often  stalactitic.     Interiorly  the  structure  may 
be  either  granular,  radiately  fibrous,  or  concentric. 

The  waters  percolating  through  the  roofs  of  limestone  caverns  hold 
some  limestone  in  solution;  and  the  deposit  which  each  successive  drop 
of  water  makes,  lengthens  out  the  cylinder;  and  not  unf requently  they 
become  yards  in  length,  or  reach  from  roof  to  floor.  The  stalactites 
are  sometimes  hollow  cylinders  when  small,  because  the  drops,  which 
follow  one  another  very  slowly,  evaporate  chiefly  at  the  outer  margin 
of  each,  the  first  one  thus  making  a  ring,  and  the  following  lengthen- 
ing the  ring  into  the  cylinder.  The  solution  is  strictly  a  solution  of 
calcium  bicarbonate;  as  evaporation  takes  place  the  excess  of  carbonic 
acid  goes  off  and  calcium  carbonate  is  deposited. 

b.  Concentric. — When  consisting  of  lamellae,  lapping  one 
over  another  around  a  centre,  a  result  of  successive  concre- 
tionary aggregations,  as  in  many  concretionary  forms,  most 
pisolite,  part  of  oolite,  some  stalactites,  etc. 

c.  Stratified,  consisting  of  layers,  as  a  result  of  deposi- 
tion :  e.g.,  some  travertine,  or  tufa. 


66  PHYSICAL   PROPERTIES   OF   MINERALS. 

d.  Banded,  straticulate  ;  color-stratified.    Like  stratified 
in  origin,  but  the  layers  thin  and  usually  indicated  only 
by  variations  in  color  or  texture;  the  banding  is  shown  in 
a  transverse  section:  e.g.,  agate,  much  stalagmite,  riband 
jasper,  some  limestone;  it  becomes  lamellar  or  slaty  when 
the  little  layers  are  separable. 

e.  Geodes. — When  a  cavity  has  been  lined  by  the  deposi- 
tion of  mineral  matter,  but  not  wholly  filled,  the  enclosing 
mineral  is  called  a  geode.     The  mineral  is  often  banded, 
owing  to  the  successive  depositions  of  the  material,  and 
frequently  has  its  inner  surface  set  with  crystals.     Agates 
are  often  slices  or  fragments  of  geodes. 

6.  Fracture. — Kinds  of  fracture  in  these  crystalline  ag- 
gregates depend  on  the  size  and  form  of  the  particles,  their 
cohesion,  and  to  some  extent  their  having  cleavage  or  not. 

Among  granular  varieties,  the  influence  of  cleavage  is  in 
all  cases  very  small,  and  in  the  finest  almost  or  quite  noth- 
ing. The  term  hackly  is  used^for  the  surface  of  fracture 
of  a  metal,  when  the  grains  are  coarse,  hard,  and  cleavable, 
so  as  to  be  sharp  and  jagged  to  the  touch;  even,  for  any 
surface  of  fracture  when  it  is  nearly  or  quite  flat,  or  not  at 
all  conchoidal;  conchoidal,  when  the  mineral,  owing  to  its 
extremely  fine  or  cryptocrystalline  texture,  breaks  with 
shallow  concavities  and  convexities  over  the  surface,  as  in 
the  case  of  flint.  The  word  conchoidal  is  from  the  Latin 
concha,  a  shell.  These  kinds  of  fracture  are  not  of  great 
importance  in  mineralogy,  since  they  distinguish  varieties 
of  minerals  only,  and  not  species. 


II.  PHYSICAL  PROPERTIES  OF  MINERALS. 

THE  physical  properties  referred  to  in  the  description 
and  determination  of  minerals  are  here  treated  under  the 
following  heads:  (1)  Hardness;  (2)  Tenacity;  (3)  Specific 
Gravity;  (4)  Refraction,  Polarization;  (5)  Diaphaneity, 
Color,  Lustre;  (6)  Electricity  and  Magnetism;  (7)  Taste 
and  Odor.  All  excepting  the  last  are  more  or  less  depend- 
ent on  the  crystallization,  the  qualities  in  each  case  being 
alike  in  crystals  in  the  direction  of  like  or  equal  axes,  and 
usually  unlike  in  the  directions  of  unlike  or  unequal  axes. 


HARDNESS— TENACITY.  67 

1.  HARDNESS. 

The  comparative  hardness  of  minerals  is  easily  ascer- 
tained, and  should  be  the  first  character  attended  to  by  the 
student  in  examining  a  specimen.  It  is  only  necessary  to 
draw  a  file  across  the  specimen,  or  to  make  trials  of  scratch- 
ing one  with  another.  As  standards  of  comparison  the 
following  minerals  have  been  selected,  increasing  gradually 
in  hardness  from  talc,  which  is  very  soft  and  easily  cut  with 
a  knife,  to  the  diamond.  This  table,  called  the  scale  of 
hardness,  is  as  follows:  Q*>  ^^^^ 

1,  talc,  common  foliated  variety;  2/nuetf'JeetH-;  3,  calcite, 
transparent  variety;  4,  fiuorite,  crystallized  variety;  5, 
apatite,  transparent  crystal;  6,  or tJwclase,  cleavable  variety; 
7,  quartz,  transparent  variety;  8,  topaz,  transparent  cr}rs- 
tal;  9,  sapphire,  cleavable  variety;  10,  diamond. 

If,  on  drawing  a  file  across  a  mineral,  it  is  impressed  as 
easily  as  fluorite,  the  hardness  is  said  to  be  4;  if  as  easily  as 
orthodase,  the  hardness  is  said  to  be  6;  if  more  easily  than 
orthoclase,  but  with  more  difficulty  than  apatite,  its  hard- 
ness is  described  as  5£  or  5 -5. 

The  file  should  be  run  across  the  mineral  three  or  four 
times,  and  care  should  be  taken  to  make  the  trial  on  angles 
equally  blunt,  and  on  parts  of  the  specimen  not  altered  by 
exposure.  Trials  should  also  be  made  by  scratching  the 
specimen  under  examination  with  the  minerals  in  the  above 
scale,  since  sometimes,  owing  to  a  loose  aggregation  of  par- 
ticles, the  file  wears  down  the  specimen  rapidly,  although 
the  particles  are  very  hard. 

In  crystals  the  hardness  is  sometimes  appreciably  different 
in  degree  in  the  direction  of  different  axes.  In  crystals  of 
mica  the  hardness  is  less  on  the  basal  plane  of  the  prism, 
that  is,  on  the  cleavage  surface,  than  it  is  on  the  sides  of 
the  prism.  On  the  contrary,  the  termination  of  a  crystal 
of  cyanite  is  harder  than  the  lateral  planes.  The  degree 
of  hardness  in  different  directions  may  be  obtained  with 
great  accuracy  by  means  of  an  instrument  called  a  sclero- 
meter. 

2.  TENACITY. 

The  following  rather  indefinite  terms  are  used  with 
reference  to  the  qualities  of  tenacity,  malleability,  and  flexi- 
bility in  minerals: 


68  PHYSICAL   PROPERTIES   OF   MINERALS. 

1.  Brittle. — When  a  mineral  breaks  easily,  or  when  parts 
of  the  mineral  separate  in  powder  on  attempting  to  cut  it. 

2.  Malleable. — When  slices  may  be  cut  off,   and  these 
slices  will  flatten  out  under  the  hammer,  as  in  native  gold, 
silver,  copper. 

3.  Sect  He. — When  thin  slices  may  be  cut  off  with  a  knife. 
All  malleable  minerals  are  sectile.     Argentite  and  cerargy- 
rite  are  examples  of  sectile  ores  of  silver.     The  former  cuts 
nearly  like  lead,  and  the  latter  nearly  like  wax,  which  it  re- 
sembles.    Minerals  are  imperfectly  sectile  when  the  pieces 
cut  off  pulverize  easily  under  a  hammer,  or  barely  hold 
together,  as  selenite. 

4.  flexible. — When  the  mineral  will  bend,  and  remain 
bent  after  the  bending  force  is  removed.     Example,  talc. 

5.  Elastic. — When,  after  being  bent,  it  will  spring  back 
to  its  original  position.     Example,  mica. 

A  liquid  is  said  to  be  viscous  when  on  pouring  it  the 
drops  lengthen  and  appear  ropy. 

3.  SPECIFIC  GRAVITY. 

The  specific  gravity  of  a  mineral  (called  also  its  density) 
is  its  weight  compared  with  that  of  some  substance  taken 
as  a  standard.  For  solids  and  liquids  distilled  water,  at 
60°  F.,  is  the  standard  ordinarily  used;  and  if  a  mineral 
weighs  twice  as  much  as  water,  its  specific  gravity  is  2;  if 
three  times  it  is  3.  It  is  then  necessary  to  compare  the 
weight  of  the  mineral  with  the  weight  of  an  equal  bulk  of 
water.  The  process  is  as  follows: 

First  weigh  a  fragment  of  the  mineral  in  the  ordinary 
way,  with  a  delicate  balance;  next  suspend  the  mineral  by 
a  hair,  or  fibre  of  silk,  or  a  fine  platinum  wire,  to  one  of 
the  scales,  immerse  it,  thus  suspended,  in  a  glass  of  distilled 
water  (keeping  the  scales  clear  of  the  water)  and  weigh  it 
again;  subtract  the  second  weight  from  the  first,  to  ascer- 
tain the  loss  by  immersion,  and  divide  the  first  by  the  dif- 
ference obtained;  the  result  is  the  specific  gravity.  The 
loss  by  immersion  is  equal  to  the  weight  of  an  equal  volume 
of  water.  The  trial  should  be  made  on  a  small  fragment; 
two  to  five  grains  are  best.  The  specimen  should  be  free 
from  impurities  and  from  pores  or  air-bubbles.  For  exact 
results  the  temperature  of  the  water  should  be  noted,  and 
an  allowance  be  made  for  any  variation  from  the  height  of 


SPECIFIC    GRAVITY. 


69 


thirty  inches  in  the  barometer.  The  observation  is  usually 
made  with  the  water  at  a  temperature  of  60°  F.;  39° -5  F., 
the  temperature  of  the  maximum  density  of  water,  is  pref- 
erable. 

The  accompanying  figure  represents  the  spiral  balance 
of  Jolly,  by  which  the  density  is  meas- 
ured by  the  torsion  of  a  spiral  brass 
wire.  On  the  side  of  the  upright  [A) 
which  faces  the  spiral  wire,  there  is  a 
graduated  mirror,  and  the  readings 
which  give  the  weight  of  the  mineral  in 
and  out  of  water  are  made  by  means  of 
an  index  (at  m)  connected  with  the 
spiral  wire;  and  its  exact  height,  with 
reference  to  the  graduation,  is  obtained 
by  noting  the  coincidence  between  it 
and  its  image  as  reflected  by  the  gradu- 
ated mirror.  c  and  dare  the  pans  in 
which  the  piece  of  mineral  is  placed, 
first  in  c,  the  one  out  of  the  water,  and 
then  in  d,  that  in  the  water. 

In  using  the  spiral  balance  the  spiral 
spring  is  put  at  any  desired  height  by 
means  of  the  sliding-rod  C.  The  stand 
B  is  raised  so  that  the  lower  pan,  d, 
shall  be  in  the  water,  while  the  other,  c, 
is  above  it.  The  position  of  the  index, 
or  signal,  m,  is  then  noted,  by  sighting 
across  it  and  observing  that  the  index 
and  the  image  of  it  in  the  mirror  are  in  the  same  horizontal 
line;  let  s  stand  for  it.  Next  put  the  fragment  of  the 
mineral  in  c,  and  drop  the  stand  B  until  the  lower  pan 
hangs  free  in  the  water,  and  note  the  position  of  m,  which  we 
may  represent  by  /;  t—s  represents  the  weight  in  the  air. 
Now  place  the  fragment  in  the  lower  pan,  and  after  adjust- 
ing again  the  stand  B,  the  position  of  m  is  noted  as  before; 
call  it  u.  Then  t  —  u  —  loss  of  weight  in  water.  From 
these  values  the  specific  gravity  is  at  once  obtained. 

Another  process,  and  one  available  for  porous  as-  well  as 
compact  minerals,  is  performed  with  a  light  glass  bottle, 
capable  of  holding  exactly  a  thousand  grains  (or  any  known 
weight)  of  distilled  water.  The  specimen  should  be  re- 
duced to  a  coarse  powder.  Pour  out  a  few  drops  of  water 


PHYSICAL   PROPERTIES   OF   MINERALS. 


from  the  bottle  and  weigh  it;  then  add  the  powdered  min- 
eral till  the  water  is  again  to  the  brim,  and  reweigh  it;  the 
difference  in  the  two  weights,  divided  by  the  loss  of  water 
poured  out,  is  the  specific  gravity  sought.  The  weight  of 
the  glass  bottle  itself  is  here  supposed  to  be  balanced  by  an 
equivalent  weight  in  the  other  scale. 

Another  method  consists  in  the  use  of  a  solution  of  a  salt 
of  high  specific  gravity.  The  potassium-mercury  iodide  is 
one  salt  so  used,  and  another  is  the  cadmium  boro-tungslate. 
The  maximum  density  of  a  solution  of  the  former  is  3*2;  of 
the  latter,  3 '6.  By  carefully  adding  water,  the  solution  is 
reduced  in  density  to  that  of  the  mineral,  or  that  in  which 
the  mineral  in  coarse  grains  will  just  float;  and  this  den- 
sity is  then  determined  by  weighing  a  given  amount  of 
the  solution.  The  process  is  used  also  for  the  separation  of 
mixed  minerals  of  unequal  density.  Details  of  the  processes 
will  be  found  in  larger  works. 

4.  REFRACTION  AND  POLARIZATION. 

Light  is  refracted  when  it  passes  from  a  rarer  medium 
through  a  denser,  as  from  air  through  water,  or  the  re- 
verse. It  is  polarized,  or  has  its  vibrations  reduced  to  vi- 
brations in  a  plane,  when  it  passes  through  a  crystal  of  un- 
equal crystallographic  axes,  or  a  fragment  of  such  a  crystal. 
Amorphous  substances  (or  those  totally  devoid  of  traces  of 
crystallization),  like  glass  and  opal,  and  crystallized  sub- 
stances of  the  isometric  system,  have  single  or  simple  refrac- 
tion ;  while  substances  crystallized  under  either  of  the  other 
systems  of  crystallization  have  double  refraction. 

SIMPLE  REFRACTION. — The  index  of  ordinary  refraction 
is  obtained  by  dividing  the  sine  of  the  angle  of  incidence  of 
the  ray  of  light  by  the  sine  of  its 
angle  of  refraction.  Thus  if  a  ray 
of  light  (ah,  Fig.  1)  strike  the  sur- 
face (MN)  of  the  denser  material  at 
an  angle  of  60°  from  the  perpendic- 
ular (the  angle  bag),  and  then  passes 
through  it  at  an  angle  of  40°  from 
the  perpendicular  (angle  cab),  the 
sine  of  60°  (ad),  divided  by  the  sine 
of  40°  (ae),  will  be  the  index  of  re- 
fraction. 
The  index  of  refraction  of  air  being  taken  as  the  unit, 


REFRACTION   AND    POLARIZATION.  71 

that  of  water,  as  experiment  has  ascertained,  is  1-335 ;  of 
fluorite,  1-434;  of  rock-salt,  T557 ;  of  spinel,  1*764;  of 
garnet,  1'815;  of  blende,  2^60;  of  diamond,  2 -439. 

Isometric  and  amorphous  substances  are  said  to  be  isofro- 
pic,  because  in  them  the  velocity  of  light  and  all  light-phe- 
nomena are  alike  in  all  directions. 

DOUBLE  REFRACTION.  POLARIZATION. — Double  refrac- 
tion is  illustrated  in  the  annexed  figure  representing  a  trans- 
parent rhombohedron  of  calcite, 
with  the  ray,  ab,  divided,  as  it  passes 
through  the  crystal,  into  two  rays  ac 
and  ac'.  When  such  a  crystal  is 
placed  over  a  dot  the  dot  appears 
double,  owing  to  the  double  refrac- 
tion. Each  of  these  rays  is  a  polar- 
ized ray. 

Such  crystals  aro  optically  either 
uniaxial  or  biaxial. 

A.  Uniaxial. — Uniaxial  substances  are  those  of  the  tetrag- 
onal and  hexagonal  systems  ;  and  the  vertical  axis,  about 
which  the  parts  are  arranged  symmetrically,  is  the  optic 
axis.  In  the  direction  of  this  axis  refraction  is  simple,  but 
in  all  other  directions  double;  and  the  divergence  is  greatest 
in  a  direction  at  right  angles  to  the  vertical  or  optic  axis. 

One  of  the  rays  has  its  vibrations  transverse  to  the  axis  : 
it  is  called  the  ordinary  ray,  because  it  obeys  the  laws  of  or- 
dinary refraction  above  explained.  The  other,  the  extraor- 
dinary ray,  has  its  vibrations  in  the  direction  of  the  axis, 
and  obeys  a  different  law,  because  the  elasticity  of  the  light- 
ether  in  this  direction  is  greater  or  less  than  in  the  trans- 
verse. If  the  index  of  refraction  of  the  extraordinary  ray 
(e)  is  greater  than  that  of  the  ordinary  (GO),  the  crystal  is 
said  to  be  positive  ;  if  less,  it  is  negative.  Calcite  is  an 
example  of  a  negative  crystal,  ac  in  Fig.  2  being  the  extra- 
ordinary ray  ;  and  quartz  is  an  example  of  a  positive. 

Plates  of  tourmaline  made  by  vertical  sections  of  a 
transparent  crystal  transmit  the  extraordinary  ray,  while 
the  ordinary  ray  is  absorbed.  Hence  such  plates  are  con- 
venient for  optical  investigations.  A  simple  polariscope 
made  of  two  tourmaline  plates  has  the  form  in  Fig.  3. 
The  effects  are  the  same  whichever  tourmaline  plate  is 
brought  to  the  eye.  The  plate  away  from  the  eye,  or  that 
receiving  the  light  for  transmission,  is  called  the  polarizer, 


PHYSICAL    PROPERTIES    OF    MINERALS. 


and  the  other  the  analyzer.  Light  passes  freely  through 
the  two  plates  as  long  as  they  have  the  position  they  had  in 
the  crystal,  that  is,  have  the  vertical  axes — the  planes  of 
vibration — of  the  two  parallel.  But  if  the  axes  are  crossed, 
by  revolving  one  plate  90°,  no  light  passes.  In  a  revolu- 


tion, light  and  dark  fields  alternate  every  90°.  Crystalline 
minerals  are  examined  by  placing  sections  of  them  between 
the  tourmalines. 

Calcite,  owing  to  the  wide  divergence  of  its  refracted 
rays,  is  commonly  used  for  polarizing  apparatus.     In  a 
4.  "nicol  prism"  of  calcite  (Fig.  4)  the  extraor- 

dinary ray  (ac'}  passes  through  the  prism,  while 
the  other  (ac)  is  got  rid  of  by  reflection  from 
the  surface  of  Canada  balsam  (mn)  along 
which  the  two  pieces  of  calcite  in  the  prism  are 
joined. 

In  a  polariscope  the  two  nicols  are  mounted 
in  tubes,  one  of  which,  if  the  instrument  is  a 
vertical  one,  is  placed  above,  and  the  other 
below,  a  stage  arranged  for  receiving  the  object 
for  examination.  One  or  both  of  the  nicols, 
and  also  the  stage,  admits  of  revolution,  in 
order  to  place  the  planes  of  vibration  of  the 
nicols  in  different  positions  as  to  one  another 
and  as  to  the  specimen  centered  on  the  stage;  and  graduated 
scales  indicate  the  angle  of  revolution  in  nicol  and  stage. 
Lenses  for  magnifying  the  object  are  added;  and  also 
others,  making  what  is  called  the  condenser,  which  is  placed 
between  the  polarizer  and  the  stage. 

In  the  ordinary  polariscope,  only  very  low  magnifying- 
powers  are  used  without  an  ocular,  and  consequently  the 
field  is  large  so  as  to  be  convenient  for  observations  on  the 
light-phenomena.  By  inserting  the  condenser  the  trans- 


REFRACTION    AND    POLARIZATION. 


73 


74  PHYSICAL   PROPERTIES   OF   MINERALS. 

mission  of  the  polarized  light  in  parallel  rays  is  changed  to 
transmission  in  convergent  rays ;  and  the  light-phenomena 
are  changed. 

In  the  polarization-microscope  (a  figure  of  which  is  here 
introduced)  higher  powers  are  used,  and  also  an  ocular  (eye- 
piece with  lenses).  The  nicols  are  at  ss  (analyzer)  and  rr 
(polarizer),;  the  supporting  tube  of  the  analyzer  revolves, 
and  rests  on  a  graduated  circle  ff}  with  a  mark  on  the 
edge  which  is  to  be  set  at  0°  to  put  the  vibration-planes  of 
the  two  nicols  in  a  crossed  position,  and  at  90°  to  make  them 
parallel.  The  tube  of  the  microscope  moves  up  and  down, 
by  the  hand,  within  the  outer  case  pp  ;  and  a  fine  adjustment 
is  obtained  with  the  screw  g,  the  surface  of  which  is  gradu- 
ated. In  the  figure  the  condenser  TT  is  in  place,  as  when 
required  for  observations  with  converging  rays  (which  are 
made  with  the  ocular  removed).  The  stage  revolves  and  has 
a  lateral  movement  by  screws  to  aid  in  centering  the  object ; 
and  to  give  further  aid,  the  tube  has  a  slight  movment  by 
the  screw  nn.  it  is  an  opening  for  inserting  a  plate  of  quartz 
(ZZ,)  for  determining  the  precise  position  when  an  axis  of 
elasticity  of  the  object  on  the  stage  coincides  with  a  vibra- 
tion-plane of  a  nicol,  and  for  other  purposes. 

On  revolving  one  of  the  nicols,  the  change  from  the 
transmission  of  light  to  its  non- transmission  by  the  analyzer, 
or  the  "  extinction  of  the  ray,"  takes  place  with  every  90° 
of  revolution,  as  with  the  tourmaline  polariscope ;  and  alike 
tor  parallel  and  converging  light. 

If  a  plate  of  a  uniaxial  crystal  cut  at  right  angles  to  the 
vertical  or  optic  axis  is  on  the  stage  centered  in  the  field  of 
view,  and  the  nicols  are  crossed  and  parallel  light •  is  used, 

the    field    remains   dark 

6.  7.  through     the     complete 

revolution  of  the  stage, 
as  in  the  case  of  isometric 
and  isomorphous  sub- 
stances; but  if  converg- 
ing light  is  used  in  the 
polariscope,  a  symmetrical 
black  cross  and  concentric 
spectrum-circles  are  seen 
when  the  nicols  are  crossed 
(Fig.  6),  and  a  light-cross  with  the  colors  reversed  (Fig.  7) 
when  they  are  parallel.  The  number  of  spectrum-ringg 


REFRACTION    AND    POLARIZATION.  75 

within  the  field  under  a  given  convergence  and  magnifying- 
power  depends  on  the  refraction  and  the  thickness  of  the 
plate  under  examination.  The  plate  may  be  so  thin  that 
it  will  have  but  one  color,  or  none.  The  tourmaline- 
polariscope  affords  the  same  cross  and  circles  or  "  interfer- 
ence-figures/' because  the  eye  is  brought  so  closely  to  the 
analyzer  in  making  observations  that  the  light  is  really 
converging  light. 

When  the  ordinary  thin  sections  mounted  on  glass  are 
examined  in  the  polarization-microscope,,  it  is  commonly  the 
case,  owing  to  the  thinness  of  the  sections,  that  few  if  any 
of  the  colored  rings  around  the  centre  of  the  black  cross 
are  in  sight.  If  the  sections  for  examination,  instead  of 
being  cut  parallel  to  the  base  of  the  crystal,  or  at  right 
angles  to  the  optic  axis,  are  cut  a  little  oblique  to  it  but  at 
right  angles  still  to  a  vertical  axial  section,  the  cross  will 
be  symmetrical,  but  its  centre  out  of  the  centre  of  the  field; 
and  if  cut  much  oblique  to  it,  its  centre  may  be  wholly  out 
of  the  field,  and  only  one  straight  black  band  be  visible. 

Circular  polarization  characterizes  quartz.  The  light- 
vibrations  instead  of  being  in  a  single  plane  rotate  either 
to  the  right  or  left,  according  as  the  crystal  is  right-handed 
or  left-handed  (p.  55).  Consequently,  a  plate  cut  at  right 
angles  to  the  optic  or  vertical  axis  has  a  colored  centre  to 
the  series  of  spectrum-circles  in  all  positions  of  the  ana- 
lyzer; moreover,  on  revolving  the  analyzer  the  color  of  the 
centre  changes  from  blue  to  yellow  and  red  in  riff  It  ^-handed 
crystals  if  the  revolution  is  to  the  right,  and  in  /e/7-handed 
when  the  revolution  is  in  the  opposite  direction. 

B.  Biaxial. — 1.  In orth< rhombic, monoclinic,  and  tridinic 
crystals  the  three  crystallographic  axes  are  unequal,  and 
there  is  unequal  elasticity  optically  in  three  directions  at 
right  angles  with  one  another:  a  maximum  axis  (a),  a  mean 
(b),  and  a  minimum  (c).  The  elasticity  in  these  directions 
is  inversely  as  the  refraction-indices  for  the  same  direc- 
tions. 

There  are  two  directions  in  which  there  is  no  double  re- 
fraction, and  these  are  the  directions  of  the  two  optic  axes. 
The  two  are  situated  in  a  plane  passing  through  the  axes  of 
maximum  and  minimum  elasticity  (a  and  c),  and  coincide 
with  lines  in  this  plane  along  which  the  elasticity  equals 
that  of  the  mean  axis.  A  line  bisecting  the  acute  angle  of 
intersection  of  the  two  optic  axes  is  called  the  acute  bisec- 


70  PHYSICAL    PROPERTIES   OF   MINERALS. 

trix,  and  that  for  the  obtuse  angle  of  intersection,  the 
obtuse  bisectrix. 

Sections  of  such  crystals  cut  at  right  angles  to  a  bisectrix 
(but  best  the  acute  bisectrix,  for  the  angle  bisected  by  the 

g  obtuse  is  too  divergent 

for  viewing  well  the 
phenomena)  show  in 
converging  polarized 
light,  when  the  plate 
under  examination  has 
the  line  joining  the 
axes  coincident  with 
the  vibration-plane  of 
either  nicol-prism,  a 
black  band  or  an  un- 
symmetrical  black 
cross,  similar  to  that  in  Fig.  8;  if  a  revolution  of  45°  is 
made,  the  form  changes  to  that  in  Fig.  9.  But  the  plates 
under  investigation  may  be  so  thin  or  the  axis  so  divergent 
that  the  axial  centres  are  not  in  the  field  of  view. 

2.  In  the  Orthorhonibic  system  the  three  axes  of  elasticity 
coincide  in  direction  with  the  crystallo^raphic  axes.     The 
plane  of  the  two  optic  axes  coincides  with  one  of  the  three 
axial  sections  :  which  of  the  three  is  to  be  determined  by 
observations  on  sections  cut  parallel  to  each. 

In  observations  made  with  parallel  light  on  sections  cut 
parallel  to  the  axial  planes,  extinction  of  the  light  takes 
place  whenever  the  cross-wires  in  the  polarization-micro- 
scope are  parallel  with  the  axes  of  elasticity  (or  the  crystal- 
lographic  axes)  in  the  section.  The  extinction,  under  the 
orthorhombic  system,  is  hence  said  to  ^parallel  extinction. 

3.  In  monoclinic  crystals  (which  have  but  one  plane  of 
symmetry — the  clinodiagonal,   and  one  axis — the   ortho- 
diagonal,  at  right  angles  to  the  plane  of  the  other  two)  one 
of  the  axes  of  elasticity  coincides  in  direction  with  the  or- 
thodiagonal,  and  the  other  two  (at  right  angles  with  it)  lie 
in  the  plane  of  symmetry.    Either  of  the  three  may  be  that 
of  maximum  (a),  mean  (b),  or  minimum  (c)  elasticity. 

The  plane  of  the  two  optic  axes  may  coincide  with  either 
of  the  three  planes  passing  through  the  axes  of  elasticity 
(one  of  which  planes  is  that  of  the  clinodiagonal  section, 
and  the  other  two  are  planes  at  right  angles  to  the  clino- 
diagonal section  passing  through  the  orthodiagonal  and  one 


REFRACTION    AND    POLARIZATION.  77 

other  of  the  axes  of  elasticity  in  that  section) ;  and  when 
situated  in  the  clinodiagonal  section  they  are  unsymmetrical 
in  crystallographic  relations,  but  when  in  either  of  the  other 
sections  they  are  situated  symmetrically  either  side  of  the 
clinodiagonal  section. 

With  reference  to  observations  with  parallel  light  in  the 
polarization-microscope,  it  is  to  be  noted  that — since  the 
plane  of  the  vertical  crystallographic  axis  and  axis  of  elas- 
ticity makes  a  right  angle  with  the  orthodiagonal,  like  the 
planes  of  vibration  of  the  crossed  nicols,  but  an  oblique 
angle  with  the  clinodiagonal,  any  section  made  in  the  or- 
thodiagonal  zone  (or  at  right  angles  to  the  clinodiagonal 
section)  will  have  extinction  parallel)  as  in  the  orthprhombic 
system;  but  in  the  case  of  sections  cut  in  other  directions, 
extinction  does  not  take  place  when  either  of  the  planes  or 
cleavage  lines  in  the  clinodiagonal  section  is  brought  to 
parallelism  with  either  vibration-plane  of  the  nicols,  and  a 
revolution  through  an  angle — different  for  different  species 
and  positions — has  to  be  made:  the  amount  of  this  angle  is 
called  the  extinction-angle  as  measured  from  the  edge  or 
cleavage-line  selected  for  the  measurement.  For  horn- 
blende and  pyroxene,  in  which  the  optic  axes  lie  in  the 
plane  of  symmetry,  the  extinction-angle  is  measured  from 
the  cleavage-lines,"  these  being  parallel  to  the  vertical  axes  ; 
it  is  15°  for  hornblende  ;  39°  for  pyroxene  ;  Avhile  parallel, 
or  0°  (expressed  by  the  symbol  || )  for  enstatite  and  hy- 
persthene  which  are  orthorhombic. 

The  following  figures  represent  clinodiagonal  sections 
of  hornblende  and  pyroxene,  having  cc  as  the  vertical 
axis,  and  aa  as  the  clinodiagonal,  with  the  angle  of  extinc- 
tion marked  upon  them.  A  A,  BB  are  the  two  optic  axes, 
and  a,  c  the  two  axes  of  elasticity. 

The  point  of  light-extinction  is  more  exactly  determin- 
able  if  a  basal  section  of  calcite  is  placed  between  the  ocular 
and  analyzer,  and  the  precise  moment  observed  when  the 
distortion  of  the  interference-figures  of  the  calcite  ceases. 
But  for  microscopic  investigations  a  quartz-plate  or  a  Cal- 
deron  artificial  twin  of  calcite  is  used.  The  quartz-plate  is 
inserted  above  the  objective.  The  nicols  being  crossed  and 
the  analyzer  revolved  until  a  particular  color,  say  violet,  is 
obtained,  then,  on  placing  the  section  on  the  stage,  the 
color  will  be  changed,  and  will  remain  different  until  one  of 
the  axes  of  elasticity  in  the  section  corresponds  with  a  vibra- 


78 


PHYSICAL   PROPERTIES   OF   MINERALS. 


tion-plane  in  the  nicols,  when  it  will  be  violet  again.     This 
is  the  point  desired. 

4.  In  the  triclinic  system,  since  there   is   no  plane  of 


HORNBLENDE. 


PYROXENE. 


symmetry,  and  the  crystallographic  axes  have  no  rectangu- 
lar intersections,  the  positions  of  the  axes  of  elasticity  and 
of  the  optic  axes  have  to  be  determined  by  the  optical  ex- 
amination of  sections  cut  in  different  directions,  and  by  the 
angles  of  extinction  measured  from  different  faces  of  the 
crystal  or  cleavage-lines.  Some  hints  as  to  the  positions  of 
the  axes  may  often  be  derived  from  their  positions  in  re- 
lated monoclinic  forms  of  similar  chemical  compounds;  as, 
for  the  triclinic  feldspars  from  the  monoclinic,  for  rhodonite 
from  pyroxene,  etc.  In  the  triclinic  feldspars  the  extinc- 
tion-angle is  usually  measured  from  the  edge  between  the 
two  cleavage-planes,  or  parallel  to  the  shorter  diagonal  of  0. 
The  angle  differs  for  the  different  kinds,  and  is  the  chief 
means  of  microscopical  determination. 

5.  Compound  crystals,  the  isometric  excepted,  are  com- 
pound in  their  optical  characters  as  well  as  form.  The 
component  parts  have  their  crystallographic  axes  in  dif- 
erent  positions,  and  hence  also  their  optical  axes ;  and  as 
a  consequence  adjoining  spectra  have  the  order  of  colors 
reversed  or  otherwise  different.  When,  in  the  optical  ex- 
aminations of  thin  slices,  halves  or  alternate  sectors,  or 
alternate  bands,  differ  as  to  the  transmission  of  light,  or  as 
to  color,  there  is  evidence  of  a  compound  structure.  In 
the  polysynthetic  twins  of  albite,  labradorite,  and  other 
triclinic  feldspars,  if  the  slice  cuts  across  the  vertical  axis, 


REFRACTION"    AND    POLARIZATION. 


79 


parallel  bands  of  light  and  darkness,  or  of  color,  indicate 
the  multiplicity  in  the  twinning,  as  the  mineral  is  revolved 
on  the  stage.  Fig.  12  (from  Hawes)  shows  the  number  of 
such  bands  observed  in  a  slice  of  labradorite  (the  frac- 
turing is  a  consequence  of  a  movement  that  took  place  in 


12. 


the  rock  after  the  mineral  had  crystallized).  Fig.  13  rep- 
resents the  peculiar  tessellation  in  the  polysynthetic  twin- 
ning of  the  feldspar,  microcline,  arising  probably  from  the 
fact  that  the  angle  between  the  two  cleavage-planes  differs 
but  19'  from  90°. 

For  fuller  details  as  to  the  methods  of  making  optical 
investigations,  see  the  Text- book  of  Mineralogy,  or  some 
other  large  work  on  the  subject. 

6.  Anomalies  in  Polarization. — There  are  some  isometric 
crystals  which  have  the  property  of  polarization.  Examples 
occur  in  crystals  of  analcite,  leu- 
cite,  alum,  boracite,  fluorite,  and 
diamond .  The  facts  as  to  analcite 
were  long  since  described  by  Sir 
David  Brewster,  and  the  annexed 
figure,  indicating  the  arrange- 
ment of  the  colors  or  spectra  in  a 
trapezohedral  crystal  of  this  spe- 
cies, is  from  his  paper.  In  some 
cases  also  there  are  variations 
from  the  isometric  angles,  which 
seem  to  point  to  a  tetragonal  or 
other  form.  Leucite  has  angles  and  optical  characters 
that  have  led  to  its  reference  to  the  tetragonal  system. 
Analogous  conditions  exist  also  in  tetragonal  and  hexagonal 
crystals.  The  latest  view  is  that  all  such  irregularities  are 
due  to  a  molecular  strain  within  the  crystals  produced  at 
the  time  of  their  formation.  It  has  long  been  known  that 


80  PHYSICAL   PROPERTIES   OF   MINERALS. 

pressure  will  cause  the  development  of  polarizing  proper- 
ties in  many  substances;  and  these  are  analogous  cases, 
except  that  the  pressure  is  a  strain  of  molecular  origin. 
Optical  characters  in  many  of  the  species  under  all  the 
systems  of  crystallization  vary  much,,  and  the  above  is  a 
prominent  source  of  these  variations. 

7.  Dichroism,  Pleochroism. — Crystals,  excepting  those  of 
the  isometric  system,  when  colored,  often  have  different 
colors  by  transmitted  light,  and  different  degrees  of  trans- 
parency in  the  directions  of  unequal  axes  at  right  angles 
to  one  another.  In  tetragonal  and  hexagonal  crystals 
there  may  be  different  colors  in  the  vertical  and  lateral 
directions;  and  in  those  under  the  other  systems  there  may 
be  different  colors  and  transparency  in  three  directions. 
Crystals  of  tourmaline  when  transparent  or  translucent  in 
a  direction  transverse  to  the  prism  are  opaque  in  a  vertical 
direction,  because  the  ordinary  ray  is  absorbed.  Zircon, 
which  in  a  transverse  direction  is  asparagus-green,  is  pinkish 
brown  in  a  vertical,  the  light  being  differently  absorbed  as 
to  its  component  colors  in  the  two  directions.  The  differ- 
ence in  the  colors  and  transparency  may  be  very  slight :  it 
is  so  in  pyroxene  and  enstatite,  while  usually  strong  in 
hornblende  and  a  hypersthene  containing  much  iron.  Epi- 
dote  is  an  example  of  a  monoclinic  mineral  with  different 
colors  in  the  three  axial  directions. 

The  different  colors  are  best  seen  by  polarized  light,  and 
this  method  may  be  used  with  very  thin  sections.  On  exam- 
ining a  plate  of  zircon  cut  parallel  to  a  face  of  the  vertical 
square  prism,  with  a  single  nicol  or  tourmaline  plate,  the 
colors  appear  alternately  as  the  plate  or  the  nicol  is  revolved. 
The  nicol  should  be  first  set  at  0°,  so  that  its  vibration- 
plane  coincides  with  the  line  0°  to  180°  on  the  stage,  and 
then  the  plate  placed  on  the  stage  and  the  stage  revolved; 
and  the  color  thus  obtained  compared  with  that  after  a 
revolution  of  90°. 


5.  DIAPHANEITY,  LUSTRE,  COLOR. 

\    n      • 

1.  DIAPHANEITY. 

Diaphaneity  is  the  property  which  many  objects  possess 
of  transmitting  light ;  or,  in  other  words,  of  permitting 
more  or  less  light  to  pass  through  them.  This  property  is 


DIAPHANEITY,    LUSTRE,    COLOR.  81 

often  called  transparency,  but  transparency  is  properly  one 
of  the  degrees  of  diaphaneity.  The  following  terms  are 
used  to  express  the  different  degrees  of  this  property: 

Transparent — when  the  outlines  of  objects,  viewed 
through  the  mineral,  are  distinct.  Example,  glass,  crys- 
tals of  quartz. 

Subtrarisparent,  or  semitransparent — when  objects  are 
seen  but  their  outlines  are  indistinct. 

Translucent — when  light  is  transmitted,  but  objects  are 
not  seen.  Loaf-sugar  is  a  good  example;  also  Carrara 
marble. 

Subtranslucent — when  merely  the  edges  transmit  light 
faintly. 

When  no  light  is  transmitted  the  mineral  is  described  as 
opaque. 

2.  LUSTRE. 

The  lustre  of  minerals  depends  on  the  nature  of  their 
surfaces,  which  causes  more  or  less  light  to  be  reflected. 
There  are  different  degrees  of  intensity  of  lustre,  and  also 
different  kinds  of  lustre. 

a.  The  kinds  of  lustre  are  six,  and  are  named  from  some 
familiar  object  or  class  of  objects. 

1.  Metallic — the  usual  lustre  of  metals.      Imperfect  me- 
tallic lustre  is  expressed  by  the  term  submetallic. 

2.  Vitreous — the  lustre  of  broken  glass.     An  imperfect 
vitreous  lustre  is  termed  subvitreous.     Both  the  vitreous 
and  subvitreous  lustres  are  common.     Quartz  possesses  the 
former  in  an  eminent  degree  ;  calcite  often  the  latter.    This 
kind  of  lustre  may  be  exhibited  by  minerals  of  any  color. 

3.  Resinous — lustre  of  the  yellow  resins.    Example,  some 
opal,  zinc  blende. 

4.  Pearly — like  pearl.     Example,  talc,  native  magnesia, 
stilbite,  etc.     When  united  with  submetallic  lustre  the 
term  metallic-pearly  is  applied. 

5.  Greasy — looking  as  if  smeared  with  oil.     Example, 
elseolite,  some  quartz. 

6.  Silky — like  silk;  it  is  the  result  of  a  fibrous  structure. 
Example,    fibrous    calcite,    fibrous    gypsum,    and    many 
fibrous  minerals,  more  especially  those  which  in  other 
forms  have  a  pearly  lustre. 

7.  Adamantine — the  lustre  of  the  diamond.    When  sub- 


82  PHYSICAL   PROPERTIES   OF   MINERALS. 

metallic,   it  is  termed  metallic  adamantine.     Example, 
some  varieties  of  white  lead-ore  or  cerussite. 

b.  The  degrees  of  intensity  are  denominated  as  follows: 

1.  Splendent — when  the  surface  reflects  light  with  great 
brilliancy  and  gives  well-defined  images.     Example,  crys- 
tals of  hematite,  cassiterite,  some  specimens  of  quartz  and 
pyrite. 

2.  Shining — when  an  image  is  produced,  but  not  a  well- 
defined  image.     Example,  calcite,  celestite. 

3.  Glistening — when  there  is  a  general  reflection  from 
the  surface,  but  no  image.     Example,  talc. 

4.  Glimmering — when  the  reflection  is  very  imperfect, 
and  apparently  from  points  scattered  over  the    surface. 
Example,  flint,  chalcedony. 

A  mineral  is  said  to  be  dull  when  there  is  a  total  absence 
of  lustre.     Example,  chalk. 


3.  COLOR. 

1.  Kinds  of  Color. — In  distinguishing  minerals,  both  the 
external  color  and  the  color  of  a  surface  that  has  been 
rubbed  or  scratched,  are  observed.  The  latter  is  called  the 
streak^  and  the  powder  abraded,  the  streak-powder. 

The  colors  are  either  metallic  or  unmet allic. 

The  metallic  are  named  after  some  familiar  metal,  as 
copper-red,  bronze-yellow,  brass-yellow,  gold-yellow,  steel- 
gray,  lead-gray,  iron-gray. 

The  unmetallic  colors  used  in  characterizing  minerals  are 
various  shades  of  white,  gray,  Hack,  blue,  green,  yellow, 
red,  and  brown. 

There  are  thus  snow-white,  reddish-white,  greenish- 
white,  milk-white,  yellowish- white. 

Bluish-gray,  smoke-gray,  greenish-gray,  pearl-gray,  ash- 
gray. 

Velvet-black,  greenish-black,  bluish-black,  grayish-black. 

Azure-blue,  violet-blue,  sky-blue,  indigo-blue. 

Emerald-green,  olive-green,  oil-green,  grass-green,  apple- 
green,  blackish-green,  pistachio-green  (yellowish). 

Sulphur-yellow,  straw-yellow,  wax-yellow,  ochre-yellow, 
honey-yellow,  orange-yellow. 

Scarlet  red,  blood-red,  flesh-red,  brick-red,  hyacinth-red, 
rose-red,  cherry-red. 


DIAPHANEITY,    LUSTRE,    COLOR.  83 

Hair-brown,  reddish-brown,  chestnut-brown,  yellowish- 
brown,  pinchbeck-brown,  wood-brown. 

A  play  of  colors : — this  expression  is  used  when  several 
prismatic  colors  appear  in  rapid  succession  on  turning  tjie 
mineral.  The  diamond  is  a  striking  example ;  also  pre- 
cious opal. 

Change  of  colors — when  the  colors  change  slowly  on  turn- 
ing in  different  positions,  as  in  labradorite. 

Opalescence — when  there  is  a  milky  or  pearly  reflection 
from  the  interior  of  a  specimen,  as  in  some  opals,  and  in 
cat's-eye. 

Iridescence — when  prismatic  colors  are  seen  within  a 
crystal;  it  is  the  effect  of  fracture,  and  is  common  in  quartz. 

Tarnish — when  the  surface  colors  differ  from  the  inte- 
rior ;  it  is  the  result  of  exposure.  The  tarnish  is  described 
as  irised  when  it  has  the  hues  of  the  rainbow. 

3.  Asterism. — Some  crystals,  especially  the  hexagonal, 
when  viewed  in  the  direction  of  the  vertical  axis,  present 
peculiar  reflections  in  six  radial  directions.     This  arises 
either  from  peculiarities  of  texture  along  the  axial  portions, 
or  from,  some  impurities.     A  remarkable  example  of  it  is 
that  of  the  asteriated  sapphire,  and  the  quality  adds  much 
to  its  value  as  a  gem.     The  six  rays  are  sometimes  alter- 
nately shorter,  indicating  the  rhombohedral  character  of 
the  crystal. 

4.  Phosphorescence. — Several  minerals  give    out    light 
either  by  friction  or  when  gently  heated.     This  property  of 
emitting  light  is  called  phosphorescence. 

Two  pieces  of  white  sugar  struck  against  one  another  give 
a  feeble  light,  which  may  be  seen  in  a  dark  place.  The 
same  effect  is  obtained  on  striking  together  fragments  of 
quartz;  and  even  the  passing  of  a  feather  rapidly  over  some 
specimens  of  zinc-blende  is  sufficient  to  elicit  light. 

Fluorite  is  the  most  convenient  mineral  for  showing  phos- 
phorescence by  heat.  On  powdering  it  and  throwing  it  on 
a  plate  of  metal  heated  nearly  to  redness,  the  whole  takes 
on  a  bright  glow.  In  some  varieties  the  light  is  emerald- 
green  ;  in  others,  purple,  rose,  or  orange.  A  massive  fluor, 
from  Huntington,  Connecticut,  shows  beautifully  the  em- 
erald-green phosphorescence.  Some  kinds  of  white  marble, 
treated  in  the  same  way,  give  out  a  bright  yellow  light. 
After  being  heated  for  a  while  the  mineral  loses  its  phos- 
phorescence ;  but  a  few  electric  shocks  will,  in  many  cases, 
to  some  degree  restore  it  again. 


84  PHYSICAL   PROPERTIES   OF   MINERALS. 


6.  ELECTRICITY  AND  MAGNETISM. 

ELECTRICITY. — Many  minerals  become  electrified  on  De- 
ing  rubbed,  so  that  they  will  attract  cotton  and  other  light 
substances  ;  and  when  electrified,  some  exhibit  positive  and 
others  negative  electricity  when  brought  near  a  delicately 
suspended  magnetic  needle.  The  diamond,  whether  pol- 
ished or  not,  always  exhibits  positive  electricity,  while  other 
gems  become  negatively  electric  in  the  rough  state,  and 
positively  only  in  the  polished  state.  Some  minerals,  thus 
electrified,  retain  the  power  of  electric  attraction  for  many 
hours,  as  topaz,  while  others  lose  it  in  a  few  minutes. 

Many  minerals  become  electric  when  heated,  and  such 
species  are  said  to  be  pyroelectric,  from  the  Greek  pur, 
fire,  and  electric. 

A  prism  of  tourmaline,  on  being  heated,  becomes  polar, 
opposite  electricity  being  developed  in  the  extremities  by 
the  heat.  The  prisms  of  tourmaline  have  different  sec- 
ondary planes  at  the  two  extremities. 

Several  other  minerals  have  this  peculiar  electric  prop- 
erty, especially  boracite  and  topaz,  which,  like  tourmaline, 
are  Jiemiliedral  in  their  modifications.  Boracite  crystallizes 
in  cubes,  with  only  the  alternate  solid  angles  similarly  re- 
placed (Figs.  39,  40,  page  26).  Each  solid  angle,  on  heat- 
ing the  crystals,  becomes  an  electric  pole  ;  the  angles  diago- 
nally opposite  are  differently  modified,  and  have  opposite 
polarity.  Pyroelectricity  has  been  observed  also  in  crystals 
that  are  not  hemihedral,  and  in  many  mineral  species.  In 
some  cases  the  number  of  poles  is  more  than  two.  In  preh- 
nite  crystals  a  large  series  occur  distributed  over  the  sur- 
face. 

MAGNETISM. — The  name  Lodestone  is  given  to  those 
specimens  of  an  ore  of  iron  called  magnetite  which  have 
the  power  of  attraction  like  a  magnet;  it  is  common  in 
many  beds  of  magnetite.  When  mounted  like  a  horseshoe- 
magnet,  a  good  lodestone  will  lift  a  weight  of  many  pounds. 
This  is  the  only  mineral  that  has  decided  magnetic  attrac- 
tion. But  several  ores  containing  iron  are  attracted  by  the 
magnet,  or,  when  brought  near  a  magnetic  needle,  will 
cause  it  to  vibrate  ;  and  moreover,  the  metals  nickel,  cobalt, 
manganese,  palladium,  platinum  and  osmium,  have  been 
found  to  be  slightly  magnetic. 


TASTE   AND   ODOR.  85 

Many  iron-bearing  minerals  become  attractable  by  the 
magnet  after  being  heated  that  are  not  so  before  heating. 
This  arises  from  a  change  of  part  or  all  of  the  iron  to  the 
magnetic  oxide. 

7.  TASTE  AND  ODOR. 

Taste  belongs  only  to  the  soluble  minerals.  The  kinds 
are — 

1.  Astringent — the  taste  of  vitriol. 

2.  Sweetish-astringent — the  taste  of  alum. 

3.  Saline — taste  of  common  salt. 

4.  Alkaline — taste  of  soda. 

5.  Cooling — taste  of  saltpetre. 

6.  Bitter — taste  of  Epsom  salts. 

7.  Sour — taste  of  sulphuric  acid. 

Odor  is  not  given  off  by  minerals  in  the  dry,  unchanged 
state,  except  in  the  case  of  a  few  gases  and  soluble  minerals. 
By  friction,  moistening  with  the  breath,  the  action  of  acids, 
and  the  blowpipe,  odors  are  sometimes  obtained  which  are 
thus  designated: 

1.  Alliaceous — the  odor  of  garlic.     It  is  the  odor  of  burn- 
ing arsenic,  and  is  obtained  by  friction,  and  more  distinctly 
by  means  of  the  blowpipe,  from  several  arsenical  ores. 

2.  Horse-radish  odor — the  odor  of  decaying  horse-radish. 
It  is  the  odor  of  burning  selenium,  and  is  strongly  perceived 
when  ores  of  this  metal  are  heated  before  the  blowpipe. 

3.  Sulphureous — odor    of    burning    sulphur.     Friction 
will  elicit  this  odor  from  pyrites,  and  heat  from  many  sul- 
phides. 

4.  Fetid — the  odor  of  rotten  eggs  or  sulphuretted  hydro- 
gen.    It  is  elicited  by  friction  from  some  varieties  of  quartz 
and  limestone. 

5.  Argillaceous — the  odor  of  moistened  clay.     It  is  given 
off  by  serpentine  and  some  allied  minerals  when  breathed 
upon.     Others,  as  pyrargillite,  afford  it  when  heated. 


86 


CHEMICAL   PROPERTIES   OF   MINERALS. 


III.   CHEMICAL  PROPERTIES  OF  MIN- 
ERALS. 

THE  chemical  properties  of  minerals  are  of  two  kinds: 
(1}  Those  relating  to  the  chemical  composition  of  minerals; 
(2)  those  depending  on  their  chemical  reactions,  with  or 
without  fluxes,  including  results  obtained  by  means  of  the 
blowpipe. 

1.  CHEMICAL  COMPOSITION. 

All  the  elements  made  known  by  chemistry  are  found  in 
minerals,  for  the  mineral  kingdom  is  the  source  of  what- 
ever living  beings — plants  and  animals — contain  or  use.  A 
list  of  these  elements,  as  at  present  made  out,  is  contained 
in  the  following  table,  together  with  the  symbol  for  each 
used  in  stating  the  composition  of  substances.  These  sym- 
bols are  abbreviations  of  the  Latin  names  for  the  elements. 
A  few  of  these  Latin  names  differ  much  from  the  English, 
as  follows: 


Stibium  Sb  =  Antimony 

Cuprum  Cu  =  Copper 

Ferrum  Fe  =  Iron 

Plumbum        Pb  =  Lead 
Hydrargyrum  Hg  =  Mercury 


Kalium  K    =  Potassium 

Argeutum  Ag  =  Silver 

Natrium  Na  =  Sodium 

Stannum  Sn  =  Tin 

Wolframium  W  =  Tungsten 


TABLE  OF  THE  ELEMENTS. 


Aluminium 

Antimony 

A rsenic 

Barium 

Beryllium 

Bismuth 

Boron 

Bromine 

Cadmium 

Caesium 

Calcium 

Carbon 

Cerium 


M 

27.4 

Chlorine 

Sb 

120 

Chromium 

As 

75 

Cobalt 

Ba< 
Be 
Bi 

137 
13.8 
210 

Copper 
Didymium 
Erbium 

B 

11 

Fluorine 

Br 

80 

Gallium 

Cd 

112 

Gold 

Cs 

133 

Hydrogen 

Ca 

40 

Indium 

C 

12 

Iodine 

Ce 

92 

Iridium 

Cl 

Cr 

Co 

Cu 

D 

E 

F 

Ga 

Au 

H 

In 

I 

Ir 


35.5 

52 

59 

63.5 

95 
166 

19 

70 

197 

1 

113.4 
127 
198 


CHEMICAL   COMPOSITION. 


8? 


Iron 

Fe 

56 

Selenium 

Lanthanum 

La 

139 

Silver 

Lead 

Pb 

207 

Silicon 

Lithium 

Li 

7 

Sodium 

Magnesium 

Mg 

24 

Strontium 

Manganese 

Mn 

55 

Sulphur 

Mercury 

Hg 

200       Tantalum 

Molybdenum 

Mo 

96     !  Tellurium 

Nickel 

Hi 

59     1  Thallium 

Niobium(Columbium)Nb(Cb)  94 

Thorium 

Nitrogen 

N 

14 

Thulium 

Osmium 

Os 

199 

Tin 

Oxygen 

O 

16 

Titanium 

Palladium 

Pd 

106 

Tungsten 

Phosphorus 

P 

31 

Uranium 

Platinum    , 

Pt 

197 

Vanadium 

Potassium 

K 

39 

Ytterbium 

Rhodium 

Ro 

104 

Yttrium 

Rubidium 

Rb 

85.4 

Zinc 

Ruthenium 

Ru 

104 

Zirconium 

Se 

Ag 

Si 

Na 

Sr 

S 

Ta 

Te 

Tl 

Th 


W 

U 

V 

Yb 

Y 

Zn 

Zr 


79.4 
108 
28 
23 
87.6 
32 
182 
128 
204 
231 
Tm      170.7 
Sn       118 
Ti         50 
184 
240 
51.3 
173 
91 
65 
90 


Germanium  is  the  name  of  another  element. 

The  combining  weights  indicate  the  proportions  in  which 
the  elements  combine.  Thus,  assuming  hydrogen,  the 
lightest  of  the  elements,  to  be  1,  or  the  unit  of  the  series, 
the  combining  weight  of  oxygen  is  16;  of  iron,  56;  of  mag- 
nesium, 24;  of  sulphur,  32;  and  so  on.  When  hydrogen 
and  oxygen  combine  it  is  in  the  ratio  of  2  pounds  of  hydro- 
gen, or  else  1  pound  of  hydrogen,  to  16  pounds  of  oxygen, 
and  two  different  compounds  thus  result.  When  oxygen 
and  magnesium  combine  it  is  in  the  ratio  of  16  pounds  of 
oxygen  to  24  of  magnesium.  Oxygen  and  iron  combine  in 
the  ratio  of  16  of  oxygen  to  56  of  iron;  or  of  24  of  oxygen 
(1-J-  times  16)  to  56.  Sulphur  and  oxygen  combine  in  the 
ratio  of  32  of  oxygen  to  32  of  sulphur;  or  of  48  to  32  of  sul- 
phur. The  combining  weights  are  often  called  the  atomic 
weights. 

The  following  is  the  manner  of  using  the  symbols:  For 
the  compound  consisting  of  hydrogen  and  oxygen  in  the 
ratio  of  2  to  16,  the  chemical  symbol  is  H20,  meaning  2  of 
hydrogen  to  1  of  oxygen.  (This  compound  is  water.)  For 
the  compound  of  oxygen  and  magnesium  just  referred  to, 
the  symbol  is  MgO;  for  the  two  compounds  of  oxygen  and 
iron,  FeO,  protoxide  of  iron;  Fe203,  sesquioxide  of  iron,  the 
ratio  of  1  to  1£  being  expressed  by  2  to  3;  for  the  two  com- 
pounds of  sulphur  and  oxygen,  S0a  and  S08, 


88  CHEMICAL   PROPERTIES   OF   MINERALS. 

Some  of  the  elements  so  closely  resemble  one  another 
that  their  similar  compounds  are  closely  alike  in  crystalli- 
zation and  other  qualities,  and  they  are  therefore  said  to  be 
isomorphous. 

This  is  true  of  iron,  magnesium,  calcium,  and  two  or 
three  other  related  elements.  In  one  group  of  compounds 
of  these  bases,  the  carbonates,  the  crystalline  form  for  each 
is  rhombohedral,  and  among  them  there  is  a  difference  of 
less  than  two  degrees  in  the  angle  of  the  rhombohedron. 
Besides  a  carbonate  of  calcium,  a  carbonate  of  magnesium, 
and  a  carbonate  of  iron,  there  is  also  a  carbonate  of  calcium 
and  magnesium,  in  which  half  of  the  calcium  of  the  first 
of  these  carbonates  is  replaced  by  half  an  atom  of  magne- 
sium; and  another  species  in  which  the  base,  instead  of 
being  all  magnesium,  is  half  magnesium  and  half  iron.  By 
half  is  here  meant  half  in  the  proportion  of  their  combin- 
ing weights. 

The  replacement  of  one  of  these  elements  by  the  other, 
and  similar  replacements  among  other  groups  of  related 
elements,  run  through  the  whole  range  of  mineral  com- 
pounds. Thus  we  have  sodium  replacing  potassium,  ar- 
senic replacing  phosphorus  and  antimony,  and  so  on. 

In  the  combinations  of  oxygen  and  'iron,  as  illustrated 
above,  oxygen  is  combined  with  the  iron  in  diiferent  pro- 
portions. FeO  contains  1  of  Fe  (iron)  to  1  of  0  (oxygen) 
and  Fe203,  or,  as  it  is  often  written,  Fe03,  contains  f  Fe 
to  1  of  0.  As  the  iron  in  each  of  these  cases  satisfies  the 
oxygen,  it  is  evident  that  the  iron  must  be  in  two  different 
states,  (1)  a  protoxide  state,  and  (2)  a  sesquioxide  state. 
One  part  of  iron  in  this  SQsquioxide  state  (=  |Fe)  often 
replaces  in  compounds  one  part  of  iron  in  the  protoxide 
state  (or  IFe),  with  no  greater  change  of  qualities  than 
happens  in  the  replacement  of  iron  by  magnesium,  or  cal- 
cium,, explained  above ;  or,  avoiding  fractions,  3  parts  of 
Fe  in  the  protoxide  state  replaces  2Fe  in  the  sesquioxide 
state.  Writing  Fe  for  the  last  2Fe,  the  statement  becomes 
1  of  Fe3  replaces  1  of  Fe.  Aluminium  occurs  only  in  the 
sesquioxide  state,  and  the  ordinary  symbol  of  the  oxide  is 
Al?03,  or  A103.  But  it  is  closely  related  to  iron  in  the  ses- 
quioxide state,  so  that,  using  the  same  mode  of  expression 
as  for  iron,  1  of  Al  replaces  1  of  Fe3,  or  1  of  Mg3,  and  so 
on.  Similarly,  writing  R  for  any  metal,  1  of  R  replaces  1 
of  E9.  Again,  in  potash  (K20),  soda  (Na30),  lithia  (LiaO), 


CHEMICAL   COMPOSITION.  89 

water  (H20),  one  of  oxygen  (0)  is  combined  severally  with 
2  of  K  (potassium),  of  Na  (sodium),,  of  Li  (lithium),  of  hy- 
drogen ;  and  hence  2K,  2Na,  2 Li,  that  is,  K2,  Na2,  Li,, 
may  each  replace  in  compounds  ICa,  or  IMg,  etc. 

The  elements  potassium,  sodium,  lithium,  hydrogen,  oi 
which  it  takes  two  parts  to  combine  with  1  of  oxygen,  are 
called  monads.  Other  elements  of  the  group  of  monads 
are  rubidium,  ccBsium,  thallium,  silver,  and  also  fluorine, 
chlorine,  bromine,  iodine.  Still  other  elements  combining 
by  two  parts  in  their  oxygen  or  sulphur  compounds,  etc., 
are  nitrogen,  phosphorus,  antimony,  boron,  niobium,  tan- 
talum, vanadium  and  gold.  For  example,  for  arsenic  there 
are  the  compounds  As2S,  As2S3,  As203,  As205,  etc.  Another 
characteristic  of  these  elements  of  the  hydrogen,  sodium, 
chlorine,  and  arsenic  groups  is  that  the  number  of  equiva- 
lents of  the  acidic  element  in  the  compounds  into  which 
they  enter  is/ with  a  rare  exception,  odd,  and  of  the  1,  3,  5, 
etc.,  series,  and  on  this  account  they  are  called  in  chemis- 
try perissads;  while  the  other  elements,  in  whose  com- 
pounds their  number  is  of  the  1,  2,  3,  etc.  (or  2,  4,  6)  series, 
are  called  artiads.  An  apparent  exception  exists  under 
the  artiads  in  the  sesquioxides,  but  this  does  not  alter  the 
general  character  of  the  series. 

The  facts  above  cited  sustain  the  general  statement  that 
Ca3,  Mg3,  Mn3,  Zn3,  Fe3,  Al,  Fe,  Mn,  have  equivalent  com- 
bining values,  and  hence  in  minerals  often  replace  one  an- 
other; and  so  also  Ca,  Mg,  Mn,  Zn,  Fe,  K2,  Na2,  Li2,  H2, 
may  replace  one  another.  Similarly,  also,  As2,  or  Sb,,  re- 
places S  in  some  minerals. 

With  reference  to  the  classification  of  minerals  the  ele- 
ments may  be  conveniently  divided  into  two  groups  :  (1) 
the  Acidic,  and  (2)  the  Basic.  The  former  includes  oxy- 
gen and  the  elements  which  were  termed  the  acidifiers  and 
acidifiable  elements  in  the  old  chemistry.  They  are  those 
which  have  been  called  in  mineralogy  the  mineralizing  ele- 
ments, since  they  are  the  elements  which  are  found  com- 
bined with  the  metals  to  make  them  ores,  that  is,  to  miner- 
alize them.  The  basic  are  the  rest  of  the  elements.  The 
groups  overlap  somewhat,  but  this  need  not  be  dwelt  upon 
here. 

The  more  important  of  the  acidic  elements  are  the  fol- 
lowing: oxygen,  fluorine,  chlorine,  bromine,  iodine,  sul- 
phur, selenium,  tellurium,  boron,  chromium,  molybdenum, 


90  CHEMICAL   PEOPERTIES   OF   MINERALS. 

tungsten,  phosphorus,  arsenic,  antimony,  vanadium,  nitro- 
gen, tantalum,  niobium,  carbon,  silicon. 

Again,  among  the  conpounds  of  these  elements  occurring 
in  the  mineral  kingdom  there  are  two  grand  divisions,  the 
binary  and  the  ternary.  The  binary  consist  of  one  or 
more  elements  of  each  of  the  acidic  and  basic  divisions,  and 
the  ternary  of  one  or  more  elements  of  each  of  these  two 
classes,  along  with  oxygen,  fluorine,  or  sulphur  as  a  third. 
The  binary  include  the  sulphides,  arsenides,  chlorides,  fluor- 
ides, oxides,  etc.,  and  the  ternary  the  sulphates,  chromates, 
bor  at  es,ar  senates,  phosphates,  silicates,  carbonates,  etc.,  and 
also  the  sulpk-arsenites  and  sulph-antimonites,  in  which  a 
basic  metal  (usually  lead,  copper,  silver)  is  combined  with 
arsenic  or  antimony  and  sulphur. 

The  following  are  examples  of  the  symbols  of  binary  and 
ternary  compounds  : 

1.  Binary. 

1.  Sulphides,  Selenides. — Ag2S  =  silver  sulphide;  Ag2Se 
=  silver  selenide;  PbS  —  lead  sulphide;  ZnS  =  zinc  sul- 
phide; FeS?  =  iron  disulphide. 

2.  Fluorides,  Chlorides,  etc. — CaF2  —  calcium  fluoride; 
AgCl  —  silver  chloride;  AgBr  =  silver  bromide;  Agl  = 
silver  iodide;  NaCl  =  sodium  chloride  (common  salt). 

3.  Oxides. — AlaO,  =  3(A1§  0)  —  aluminium  sesquioxide; 
As203  =  arsenic  trioxide;  As20B  =  arsenic  pentoxide;  BaO 
=  barium  oxide;  Be203  =  beryllium  oxide;  B203  =  boron 
trioxide  (boracic  acid) ;  CaO  =  calcium  oxide  (lime);  CeO 
=  ceria;  C0?  —  carbon  dioxide  (carbonic   acid);  Cr03  = 
chromium  trioxide  (chromic  acid);  Cu?0  =  copper  subox- 
ide;   CuO  =  copper  oxide;    DiO  =  didymia;  H20  =  hy- 
drogen oxide  (water) ;  FeO  —  iron  oxide .;  Fe?03  =  iron 
sesquioxide;    PbO  =  lead    oxide;   LiaO  =  lithium  oxide; 
MgO  =  magnesium    oxide ;     MnO  =  manganese    oxide ; 
Mn,0s  =  manganese  sesquioxide;  MnO,  —  manganese  di- 
oxide; P20&  •=  phosphorus  pentoxide;  K20  —   potassium 
oxide;   Si02   —  silicon    dioxide  (silica);  Na20   —  sodium 
oxide;   SrO  =  strontium  oxide;  S02   =   sulphur  dioxide 
(sulphurous  acid);  S03  =  sulphur  trioxide;    Sn02  =   tin 
dioxide ;  Tm203   —  thulia;  V205  =  vanadium  pentoxide 
(vanadic  acid);  W03  =  tungsten  trioxide  (tungstic  acid); 


CHEMICAL   COMPOSITION.  91 

5Tb2Os  =  ytterbia;  ZnO  =  zinc  oxide;  Zr03  =  zirconium 
dioxide. 

The  composition  of  these  compounds  may  be  obtained 
from  the  table  of  combining  weights,  page  86.  For  exam- 
ple, with  reference  to  the  first  of  them  (AgaS),  the  table 
gives  for  the  combining  weight  of  silver  (Ag),  108,  and  for 
that  of  sulphur,  32.  The  elements  exist  in  the  compound 
therefore  in  the  proportion  of  216  to  32,  and  from  it  the 
composition  of  a  hundred  parts  is  easily  deduced. 

If  the  formula  were  (Ag2,  Pb)S,  signifying  a  silver-and- 
lead  sulphide,  and  if  the  silver  and  lead  were  in  the  ratio 
of  1  to  1,  then  once  the  combining  weight  of  silver  is  taken ; 
that  is,  108,  and  half  the  atomic  weight  of  lead,  which  is 
103*5;  and  the  sum  of  these  numbers,  with  32  for  the  sul- 
phur, expresses  the  ratio  of  the  three  ingredients. 

For  A1203  we  find  the  combining  weight  of  aluminium 
27*4;  doubling  this  for  A12  makes  54-8.  Again,  for  oxygen, 
we  find  16;  and  three  times  16  is  48.  54*8  to  48  is  there- 
fore the  ratio  of  aluminium  to  the  oxygen  in  A1208,  from 
which  the  percentage  proportion  may  be  obtained. 


2.    Ternary  Oxygen  Compounds. 

Silicates. — Of  these  compounds  there  are  two  prominent 
groups.  In  one  of  these  groups  the  general  formula  is 
R03Si,  and  in  the  other  R204Si.  In  both  of  these  formu- 
las, K  stands  for  any  basic  elements  in  the  protoxide-  state, 
as  Ca,  Mg,  Fe,  etc.,  either  alone  or  in  combination.  If 
the  basic  element  is  Mg  (magnesium)  they  become  Mg08Si, 
and  Mg04Si  (sometimes  also  written  MgO  -f-  Si02  and 
2MgO  +  Si02,  this  being  the  old  style).  In  the  first  of 
these  formulas  the  combining  values  of  the  basic  element 
R  and  the  acidic  element  or  silicon,  as  measured  by  their 
combinations  with  oxygen,  are  in  the  proportion  of  1  to  2, 
for  R  stands  for  an  element  in  the  protoxide  state,  while  Si 
stands  for  silicon,  which  is  in  the  dioxide  state,  its  oxide 
being  a  dioxide;  and  hence  the  minerals  so  constituted  are 
called  Bisilicates.  In  the  second  of  these  formulas  this 
ratio  is  2  to  2,  or  1  to  1,  and  hence  these  are  called  Unisili- 
cates.  The  second  style  of  formula  (the  old  style)  has  the 
advantage  of  expressing  the  bases  and  acids  obtained  in  an 
analysis  and  mentioned  in  the  tables  of  percentage  results 


92  CHEMICAL   PROPEETIES   OF   MINERALS. 

Multiplying  these  formulas  by  3,  they  become  R309Sis, 
and  (2R3)012Si3;  and  the  same  composition  is  expressed. 
In  this  form  the  substitution  of  sesquioxide  bases  for  pro- 
toxide may  be  indicated:  thus,  R3ROJ2Si3  signifies  that 
half  of  the  2R3  is  replaced  by  Al  or  fee,  or  some  other  ele- 
ment in  the  sesquioxide  state. 

There  are  also  some  species  in  which  the  ratio  is  1  to  less 
than  1,  and  these  are  called  Subsilicates. 

The  ratio  here  referred  to  is  the  oxygen  ratio  or  the 
quantivalent  ratio. 

The  other  ternary  compounds  require  no  special  remarks 
in  this  place. 

2.     CHEMICAL  REACTIONS. 
1.   Trials  in  the  wet  ivay. 

1.  Test  for  Carbonates. — Into  a  test-tube  put  a  little  hy- 
drochloric acid  diluted  with  one  half  water,  and  add  a 
small  portion  in  powder  of  the  mineral.     With  a  carbonate, 
there  will  be  a  brisk  effervescence  caused  by  the  escape  of 
carbonic  dioxide  (carbonic  acid),  when  heat  is  applied,  if 
not  before.     With  calcium  carbonate  no  heat  or  pulveriza- 
tion is  necessary. 

2.  Test  for  Gelatinizing  Silica. — Some  silicates,  as  neph- 
elite  and  many  zeolites,  when  powdered  and  treated  with 
strong  hydrochloric  acid,  are  decomposed,  and  deposit  the 
silica  in  the  state  of  a  jelly.     The  experiment  may  be  per- 
formed in  a  test-tube,  or  small  glass  flask.     Sometimes  the 
evaporation  of  the  liquid  nearly  to  dryness  is  necessary  in 
order  to  obtain  the  jelly.     Some  silicates  do  not  afford  the 
jelly  unless  they  have  been  previously  ignited  before  the 
blowpipe,  and  some  gelatinizing  silicates  lose  the  power  on 
ignition. 

Test  for  Soda  in  some  Silicates. — When  nephelite  is 
treated  with  hydrochloric  acid  the  solution  deposits,  on 
evaporation,  cubes  of  common  salt  (sodium  chloride);  and 
in  this  and  some  other  sodium  silicates,  if  the  hydrochloric 
solution  is  treated  with  a  concentrated  solution  of  uranium 
acetate,  yellow  tetrahedrons  of  sodium  uranate  are  formed. 

3.  Decomposability  -of  Minerals  by  Acids. — To  ascertain 
whether  a  mineral  is  decomposable  by  acids  or  not,  it  is 
very  finely  powdered  and  then  boiled  with  strong  hydro- 


CHEMICAL   REACTIONS.  93 

chloric  acid,  or,  in  case  of  many  metallic  minerals,  with  nit- 
ric acid.  In  some  cases  (as  leu  cite,  scapolite,  labradorite, 
etc.),  where  no  jelly  is  formed,  there  is  a  deposit  of  silica  in 
a  pulverulent  state.  With  the  sulphides  and  nitric  acid 
there  is  often  a  deposit  of  sulphur,  which  usually  floats  upon 
the  surface  of  the  fluid  as  a  dark  spongy  mass;  with  hydro- 
chloric acid  and  some  sulphides,  sulphuretted  hydrogen  is 
given  off.  Some  oxides,  and  also  some  sulphates  and  many 
phosphates,  are  soluble  entirely  without  effervescence. 
But  many  minerals  resist  decomposition  with  nitric  acid  as 
well  as  hydrochloric.  It  is  sometimes  difficult  to  tell  whether 
a  mineral  is  decomposed  with  the  separation  of  the  silica  or 
whether  it  is  unacted  upon.  In  such  a  case  a  portion  of 
the  clear  fluid  is  neutralized  by  soda  (sodium  carbonate), 
and  if  anything  has  been  dissolved  it  will  usually  be  pre- 
cipitated. 

4.  Test  for  Lime  in  Apatite. — A  solution  of  apatite  in 
hydrochloric  acid,  if  treated  with  sulphuric  acid,  deposits 
gypsum  freely. 

5.  Test  for  Titanium  in  Menaccanite. — The  pulverized 
mineral,  heated  with  hydrochloric  acid,  is  slowly  dissolved ; 
the  yellow  solution,  filtered  from  the  undecomposed  mineral 
and  boiled  with  the  addition  of  tin-foil,  assumes  a  beautiful 
blue  or  violet  color — a  result  not  obtained  with  hematite, 
the  mineral  it  most  resembles. 

6.  Test  for  Fluorine. — Most  fluorides  (as  fluorite,  cryolite, 
etc. )  are  decomposed  by  strong  heated  sulphuric  acid,  and 
give  out  fluorine  which  will  etch  a  glass  plate  in  reach  of 
the  fumes.     The  trial  may  be  made  in  a  lead  cup,  and  the 
glass  put  over  it  as  a  loose  cover. 

7.  Test  for  Native  Iron. — Dilute  nitrate  of  copper  de- 
posits copper  on  a  clean  plate  of  iron. 

8.  Test  for  Phosphoric  Acid  in,  Apatite,  etc. — A  concen- 
trated nitric-acid  solution  of  ammonium  molybdate  acts  on 
apatite  and  deposits  yellow  octahedrons  or  dodecahedrons 
of  ammonium  phosphomolybdate;  and  a  drop  of  the  solu- 
tion will  produce  this  result  with  the  apatite  of  a  thin  sec- 
tion prepared  for  microscopic  study. 

2.  Trials  luith  the  Blowpipe. 

The  blowpipe,  in  its  simplest  form,  is  merely  a  bent  tube 
of  small  size,  eight  to  ten  inches  long,  terminating  at  one 


94  CHEMICAL   PROPERTIES   OF   MINERALS. 

end  in  a  minute  orifice.  It  is  used  to  concentrate  the  flame 
on  a  mineral,  and  this  is  done  by  blowing  through  it  while 
the  smaller  end  is  just  within  the  flame. 

The  annexed  figure  represents  the  form  commonly  em- 
ployed, except  that  it  often  has  a  trumpet-shaped  mouth- 
piece. It  contains  an  air-chamber  (o)  to  receive  the  moisture 
which  is  condensed  in  the  tube  during  the  blowing;  the 
moisture,  unless  thus  removed,  is  often  blown  through  the 
small  aperture  and  interferes  with  the  experiment.  The 
jet,  jt,  is  movable,  and  it  is  desirable  that  it  should  be 
made  of  platinum,  in  order  that  it  may  be 
cleaned  when  necessary,  either  by  high  heating 
or  by  immersion  in  an  acid. 

In  using  the  blowpipe  it  is  necessary  to 
breathe  and  blow  at  the  same  time,  that  the  oper- 
ator may  not  interrupt  the  flame  in  order  to  take 
breath.  Though  seemingly  absurd,  the  neces- 
sary tact  may  easily  be  acquired.  Let  the  stu- 
dent first  breathe  a  few  times  through  his  nos- 
trils while  his  cheeks  are  inflated  and  his  mouth 
closed.  After  this  practice  let  him  put  the 
blowpipe  to  his  mouth  and  he  will  find  no  diffi- 
culty in  breathing  as  before  while  the  muscles 
of  the  inflated  cheeks  are  throwing  the  air  they 
contain  through  the  blowpipe.  When  the  air  is 
nearly  exhausted  the  mouth  may  again  be  filled 
through  the  nose  without  interrupting  the  pro- 
cess of  blowing. 

The  flame  of  a  candle,  or  a  lamp  with  a  large  wick,  may 
be  used;  and  when  so,  it  should  be  bent  in  the  direction  the 
flame  is  to  be  blown.  But  it  is  far  better,  when  gas  can  be 
had,  to  use  a  Bunsen's  burner. 

The  flame  has  the  form  of  a  cone,  yellow  without  and 
blue  within.  The  heat  is  most  intense  just  beyond  the  ex- 
tremity of  the  blue  flame.  In  some  trials  it  is  necessary 
that  the  air  should  not  be  excluded  from  the  mineral  during 
the  experiment,  and  when  this  is  the  case  the  outer  flame 
is  used.  The  outer  is  called  the  oxidizing  flame  (because 
oxygen,  one  of  the  constituents  of  the  atmosphere,  com- 
bines in  many  cases  with  some  parts  of  the  assay,  or  sub- 
stance under  experiment),  and  the  inner  the  reducing  flame. 
In  the  latter  the  carbon  and  hydrogen  of  the  flame,  which 
are  in  a  high  state  of  ignition,  and  which  are  enclosed  from 


CHEMICAL    REACTIONS.  95 

the  atmosphere  by  the  outer  flame,  tend  to  unite  with  the 
oxygen  of  any  substance  that  is  inserted  in  it.  Hence  sub- 
stances are  reduced  in  it. 

The  mineral  is  supported  in  the  flame  either  on  charcoal ; 
or  by  means  of  steel  forceps  (as  in  the  annexed  figure)  with 


platinum  extremities  (ab),  opened  by  pressing  on  the  pins 
p p\  or  on  platinum  wire  or  foil. 

To  ascertain  i1c&  fusibility  of  a  mineral,  the  fragment  for 
the  platinum  forceps  should  not  be  larger  than  the  head  of 
a  pin,  and,  if  possible,  should  be  thin  and  oblong,  so  that 
the  extremity  may  project  beyond  the  platinum.  The  fu- 
sible metals  alloy  readily  with  platinum.  Hence  com- 
pounds of  lead,  arsenic,  antimony,  etc.,  must  be  guarded 
against.  These  compounds  are  tested  on  charcoal.  The 
forceps  should  not  be  used  with  the  fluxes,  but  instead 
either  charcoal  or  the  platinum  wire  or  foil. 

The  charcoal  should  be  firm  and  well  burnt;  that  of  soft 
wood  is  the  best.  It  is  employed  especially  for  the  reduc- 
tion of  oxides,  in  which  the  presence  of  carbon  is  often 
necessary,  and  also  for  observing  any  substances  which  may 
pass  off  and  be  deposited  on  the*  charcoal  around  the  assay. 
These  coatings  are  usually  oxides  of  the  metals,  which  are 
formed  by  the  oxidation  of  the  volatile  metals  as  they  issue 
from  the  reduction-flame. 

The  platinum  wire  is  employed  in  order  to  observe  the 
action  of  the  fluxes  on  the  mineral,  and  the  colors  which 
the  oxides  impart  to  the  fluxes  when  dissolved  in  them. 
The  wire  used  is  No.  27.  This  is  cut  into  pieces  about 
three  inches  long,  and  the  end  is  bent  into  a  small  loop,  in 
which  the  flux  is  fused.  This  makes  what  is  called  a  bead. 
When  the  experiment  is  complete  the  beads  are  removed  by 
uncoiling  the  loop  and  drawing  the  wire  through  the  finger- 
nails. After  use  for  awhile  the  end  breaks  off,  because  pla- 
tinum is  acted  upon  by  the  soda,  and  then  a  new  loop  has 
to  be  made.  Dilute  sulphuric  acid  will  remove  any  of  the 
flux  that  may  remain  upon  it  after  a  trial  has  been  made. 

Glass  tube  is  employed  for  various  purposes.  It  should 
be  from  a  line  to  a  fourth  of  an  inch  in  bore.  It  is  cut  into 


9G  CHEMICAL    PROPERTIES    OF    MINERALS. 

pieces  four  to  six  inches  long,  and  used  in  some  cases  with 
both  ends  open,  in  others  with  one  end  closed.  In  the 
closed  tube,  either  heated  directly  over  the  Bunsen  burner, 
or  with  the  aid  of  the  blowpipe,  volatile  substances  in  the 
assay  are  vaporized  and  condensed  in  the  upper  colder  part 
of  the  tube,  where  they  may  be  examined  by  a  lens  if  neces- 
sary, or  by  further  heating.  The  odor  given  off  may  also 
be  noted;  also  the  acidity  of  any  fumes  by  inserting  a  small 
strip  of  litmus  paper  in  the  mouth  of  the  tube,  for  acids 
redden  litmus  paper.  The  closed  tube  is  used  to  observe 
all  the  effects  that  may  take  place  when  a  substance  ds 
heated  out  of  contact  with  the  air.  In  the  open  tube  the 
atmosphere  passes  through  the  tube  in  the  heating,  and  so 
modifies  the  result.  The  assay  is  placed  an  inch  or  an  inch 
and  a  quarter  from  the  lower  end  of  the  tube ;  the  tube 
should  be  held  nearly  horizontally,  to  prevent  the  assay 
from  falling  out.  The  strength  of  the  draught  depends 
upon  the  inclination  of  the  tube,  and  in  special  cases  it 
should  be  inclined  as  much  as  possible. 

The  most  common  flaxes  are  borax  (sodium  biborate), 
sail  of  phosphorus  (sodium  and  ammonium  phosphate),  and 
soda  (sodium  carbonate,  either  the  carbonate  or  bicarbon- 
ate of  soda  of  the  shops).  These  substances,  when  fused 
and  highly  heated,  are  very  powerful  solvents  for  metallic 
oxides.  They  should  be  pure  preparations.  The  borax 
and  soda  are  much  the  most  important.  In  using  the  pla- 
tinum wire,  the  loop  may  be  highly  heated,  and  then  a  por- 
tion of  the  borax  or  soda  may  be  taken  up  by  it,  and  by 
successive  repetitions  of  this  process  the  requisite  amount  of 
the  flux  may  be  obtained  on  the  wire.  Then,  by  bringing 
the  melted  flux  of  the  loop  into  contact  with  one  or  more 
grains  of  the  pulverized  mineral,  the  assay  is  made  ready 
for  the  trial.  With  soda  and  quartz  a  perfectly  clear  glob- 
ule is  obtained,  cold  as  well  as  hot,  if  the  flux  is  used  in 
the  right  proportion.  Some  oxides  impart  a  deep  and 
characteristic  color  to  a  bead  of  borax.  In  other  cases  the 
color  obtained  is  more  characteristic  when  salt  of  phos- 
phorus is  employed.  The  color  obtained  in  the  outer  flame 
is  often  different  from  that  which  is  obtained  in  the  inner 
flame.  The  beads  are  sometimes  transparent  and  some- 
times opaque.  If  too  much  substance  is  employed  the 
beads  will  be  opaque  when  it  is  desired  that  they  should  be 
transparent,  and  in  such  cases  the  experiment  should  be  re- 


CHEMICAL    REACTIONS.  97 

peated  with  less  substance.  In  many  cases  pulverized  min- 
eral and  the  flux,,  a  little  moistened,  are  mixed  together  into 
a  ball  upon  charcoal,  especially  in  the  experiments  with 
soda. 

In  the  examination  of  sulphides,  arsenides,  antimonides 
and  related  ores,  the  assay  should  be  roasted  before  using  a 
flux,  in  order  to  convert  the  substance  into  an  oxide.  This 
is  done  by  spreading  the  substance  out  on  a  piece  of  char- 
coal and  exposing  it  to  a  gentle  heat  in  the  oxidizing  flame. 
The  sulphur,  arsenic,  antimony,  etc.  then  pass  off  as  ox- 
ides in  the  form  of  vapors,  leaving  the  non-volatile  metals 
behind  as  oxides.  The  escaping  sulphurous  acid  gives  the 
ordinary  odor  of  burning  sulphur  ;  arsenous  acid,  from  ar- 
senic present,  the  odor  of  garlic,  or  an  alliaceous  odor ;  se- 
lenous  acid,  from  selenium  present,  the  odor  of  decaying 
horse-radish  ;  while  antimony  fumes  are  dense  white,  and 
have  no  odor. 

The  following  is  the  scale  of  fusibility  which  has  been 
adopted,  beginning  with  the  most  fusible : 

1.  STIBNITE. — Fusible  in  large  pieces  in  the  candle  flame. 

2.  NATROLITE. — Fusible  in  small  splinters  in  the  candle 
flame. 

3.  ALMAN DINE,  or  bright-red  GARNET. — Fusible  in  large 
pieces  with  ease  in  the  blowpipe  flame. 

4.  ACTINOLITE. — Fusible  in  large  pieces  with  difficulty 
in  the  blowpipe  flame. 

5.  ORTHOCLASE,  or  common  feldspar.     Fusible  in  small 
splinters  with  difficulty  in  the  blowpipe  flame. 

6.  BRONZITE.     Scarcely  fusible  at  all. 

The  color  of  the  flame  is  an  important  character  in  connec- 
tion with  blowpipe  trials.  When  the  mineral  contains 
sodium  the  color  of  the  flame  is  deep  yellow,  and  this  is 
generally  true  in  spite  of  the  presence  of  other  related  ele- 
ments. When  sodium  (or  soda)  is  absent,  potassium  (or 
potash)  gives  a  pale  violet  color;  calcium  (or  lime)  a  pale 
reddish  yellow;  lithium,  a,  deep  purple-red,  as  in  lithia- 
mica;  strontium,  a  bright  red,  this  element  being  the  usu- 
al source  of  the  red  color  in  pyrotechny;  copper,  emerald 
green;  phosphates,  bluish  green;  boron,  yellowish  green; 
copper  chloride,  azure-blue.  Beads  should  be  examined  by 
daylight  only,  and  should  be  held  in  such  position  that  the 
color  is  not  modified  by  green  trees  or  other  bright  objects 
when  examined  by  transmitted  light.  Colored  flames  are 
7 


98  CHEMICAL   PROPERTIES   OF   MINERALS. 

seen  to  best  advantage  when  some  black  object  is  beyond 
the  flame  in  the  line  of  vision. 

It  is  also  to  be  noted,  in  the  trials,  whether  the  assay 
heats  up  quietly  or  with  decrepitation;  whether  it  fuses 
with  effervescence  or  not,  or  with  intumescence  or  not; 
whether  it  fuses  to  a  bead  which  is  transparent,  clouded,  or 
opaque;  whether  blebby  (containing  air-bubbles)  or  not; 
whether  scoria-like  or  not. 

Testing  for  Water. — The  powdered  mineral  is  put  at  the 
bottom  of  a  closed  glass  tube,  and  after  holding  the  ex- 
tremity for  a  moment  in  the  flame  of  a  Bunsen's  burner, 
moisture,  if  any  is  present,  will  have  escaped  and  be  found 
condensed  on  the  inside  of  the  tube,  above  the  heated 
portion.  Litmus  or  turmeric  paper  is  used  to  ascertain  if 
the  water  is  acid  or  alkaline,  acids  changing  the  blue  of  lit- 
mus paper  to  red,  and  alkalies  the  yellow  of  turmeric  paper 
to  brown. 

Testing  for  an  Alkali. — If  the  fragment  of  a  mineral, 
heated  in  the  platinum  forceps,  contains  an  alkali,  it  will 
often,  after  being  highly  heated,  give  an  alkaline  reaction 
when  placed,  after  moistening,  on  turmeric  paper,  turning 
it  brown.  This  test  is  applicable  to  those  salts  which,  on 
heating,  part  with  a  portion  of  their  acid  and  are  rendered 
caustic  thereby.  Such  are  the  carbonates,  sulphates,  ni- 
trates, and  chlorides  of  the  alkaline  metals. 

Testing  for  Alumina  or  Magnesia. — Cobalt  nitrate,  in 
solution,  is  used  to  distinguish  an  infusible  and  colorless 
mineral  containing  aluminium  from  one  containing  mag- 
nesium. A  fragment  of  the  mineral  is  first  ignited,  and 
then  wet  with  a  drop  or  two  of  the  cobalt  solution  and 
heated  again.  The  aluminium  mineral  will  assume  a  blue 
color,  and  the  magnesium  mineral  a  pale  red  or  pink. 

Any  fusible  silicate,  when  moistened  with  cobalt  nitrate 
and  ignited,  will  assume  a  blue  color,  hence  this  tost  is  only 
decisive  in  testing  infusible  substances. 

Infusible  zinc  compounds,  when  moistened  with  cobalt 
nitrate,  assume  a  graen  color. 

Testing  for  Lithium. — Some  lithium  minerals  give  the 
bright  purple-red  flame  if  simply  heated  in  the  platinum 
forceps.  In  other  cases  mix  the  powdered  mineral  with 
one  part  of  fluorite  and  one  of  potassium  bisulphate.  Make 
the  whole  into  a  paste  with  a  little  water,  and  heat  it  on 
the  platinum  wire  in  the  blue  flame. 


CHEMICAL   REACTIONS.  99 

Testing  for  Boron. — When  the  bright  yellow-green  of 
boron  is  not  obtained  directly  on  heating  the  mineral  con- 
taining it,  one  part  of  the  powdered  mineral  should  be 
mixed  with  one  part  of  powdered  fluorite  and  three  of  po- 
tassium bisulphate;  and  then  treated  as  in  the  last.  The 
green  color  appears  at  the  instant  of  fusion. 

Testing  for  Fluorine. — To  detect  fluorine  in  fluorides 
mix  a  little  of  the  powdered  substance  with  potassium  bi- 
sulphate, put  the  mixture  in  a  closed  glass  tube  and  fuse 
gently.  The  bisulphate  gives  off  half  of  its  sulphuric  acid 
at  a  high  temperature,  which  acts  powerfully  on  anything 
it  can  attack.  If  a  fluoride  is  present,  hydrofluoric  acid 
will  be  given  off,  and  the  walls  of  the  tube  will  be  found 
roughened  and  etched  when  the  tube  is  broken  open  and 
cleaned  after  the  experiment.  If  a  silicate  containing 
fluorine  be  powdered  and  mined  with  previously  fused  salt 
of  phosphorus,  and  heated  in  the  open  tube  by  blowing  the 
flame  into  the  lower  end  of  the  tube,  hydrofluoric  acid  is 
given  off,  and  the  tube  is  corroded  just  above  the  assay. 

Silicates. — Nearly  all  silicates  undergo  decomposition 
with  salt  of  phosphorus,  setting  free  the  silica,  forming  a 
bead  which  is  clear  while  hot  and  has  a  skeleton  of  silica 
floating  in  it.  The  bead  is  sometimes  clear  also  when  cold. 

Iron. — Minerals  containing  much  iron  produce  a  mag- 
netic globule  when  highly  heated.  Usually  the  reducing 
flame  is  required,  and  sometimes  the  use  of  soda.  With 
borax  iron  gives  a  bead  with  the  oxidizing  flame  which  is 
yellow  while  hot,  but  colorless  on  cooling,  and  which  in  the 
reducing  flame  becomes  bottle-green. 

Cobalt. — Minerals  containing  cobalt  afford,  with  borax,  a 
beautiful  blue  bead.  If  sulphur  or  arsenic  is  present  it 
should  be  first  roasted  off  on  charcoal. 

Nickel. — In  the  oxidizing  flame  with  borax,  the  bead  is 
violet  when  hot,  and  red-brown  on  cooling.  In  the  reduc- 
ing flame  the  glass  becomes  gray  and  turbid  from  the  sepa- 
ration of  metallic  nickel,  and  on  long  blowing,  colorless. 
The  reaction  is  obscured  by  the  presence  of  cobalt,  iron, 
and  copper. 

Manganese. — With  borax  in  the  oxidizing  flame,  the  bead 
is  a  deep  violet-red,  and  almost  black  if  too  much  of  the 
mineral  is  used.  To  see  the  color,  examine  by  transmitted 
light.  With  soda  in  the  same  flame  the  opaque  bead  is 
bluish  green. 


100  CHEMICAL    PROPERTIES    OF    MINERALS. 

Chromium. — With  borax,  both  in  the  oxidizing  and  re- 
ducing flame,  the  bead  is  bright  emerald-green. 

Titanium.—  Titanium  oxide  with  salt  of  phosphorus  on 
platinum  wire  in  O.F.  dissolves  to  a  clear  glass,  which,  if 
much  is  present,  becomes  yellow,  while  hot  and  colorless  on 
cooling;  but  in  R.F.  the  hot  globule  obtained  in  O.F.  red- 
dens -and  assumes  finally  a  beautiful  violet  color.  On  char- 
coal with  tin  the  glass  becomes  violet  if  there  is  not  too 
much  iron  present. 

Zinc. — Zinc  and  some  of  its  compounds  when  heated 
cover  the  charcoal  with  zinc  oxide,  which  is  yellow  while 
hot,  but  white  on  cooling;  and  this  coating,  if  wet  with 
cobalt  solution  and  then  heated,  assumes  a  fine  yellowish 
green  color  which  is  most  distinct  when  cold. 

Lead,  copper,  tin,  silver,  when  characterizing  a  mineral, 
give  with  soda  in  the  reducing  flame  minute  metallic 
globules,  which  are  malleable,  or  may  be  cut  with  a  knife; 
they  can  be  distinguished  by  their  well-known  physical 
properties.  When  two  or  more  of  these  metals  occur  to- 
gether, or  iron  is  also  present,  the  globules  consist  usually 
of  an  alloy  of  the  metals. 

Lead. — When  the  mineral  is  treated  with  soda  on  char- 
coal in  the  oxidizing  flame,  the  yellow  oxide  coats  the  char- 
coal around  the  assay. 

Copper. — The  flame  is  colored,  in  most  cases,  bright 
green.  With  borax  or  salt  of  phosphorus  in  the  reducing 
flame  the  bead  is  red.  In  the  oxidizing  flame  the  bead  is 
green  when  hot,  and  becomes  blue  or  greenish  blue  on  cool- 
ing. 

Mercury. — Heated  in  the  closed  tube  with  soda,  a  sub- 
limate of  metallic  mercury  covers  the  inside  of  the  tube. 

Silver. — If  the  silver  is  in  very  small  quantities,  as  in 
argentiferous  galena,  the  assay  is  put  into  a  little  cup  made 
of  bone-ashes  (bone  burnt  white  and  finely  pulverized),  and 
subjected  to  the  oxidizing  flame;  the  lead  is  oxidized  and 
sinks  into  the  bone-ashes,  leaving  the  silver  a  brilliant 
globule  on  the  cupel.  Before  cupellation  it  is  often  neces- 
sary to  melt  the  assay  together  with  some  borax  and  pure 
lead  in  a  hole  on  charcoal.  By  this  process  the  sand  and 
impurities  are  removed,  and  a  globule  of  lead  is  obtained 
which  contains  all  the  silver,  and  which  may  be  separated 
from  the  slag  and  be  oxidized  as  above. 

Arsenic. — In  the  closed  tube  arsenic  sublimes  and  coats 


CHEAHCAL    REACTIONS.  101 

the  tube  with  brilliant  grains,  or  a  crust,  of  metallic  arsenic. 
If  the  mineral  contains  sulphur  as  well  as  arsenic,  subli- 
mates of  the  yellow  and  red  arsenic  sulphides  (orpiment 
and  realgar)  are  often  formed.  In  the  open  tube  a  subli- 
mate of  white  arsenous  acid  is  formed,  which  condenses  in 
bright  crystals  on  the  walls  of  the  tube,  and  a  strong  garlic 
odor  is  given  off.  On  charcoal  the  alliaceous  odor  is  at  once 
perceptible. 

Antimony. — In  the  closed  tube,  when  sulphur  is  present, 
the  assay  yields  a  sublimate  which  is  black  when  hot, 
brown-red  when  cold.  In  the  open  tube  dense  white 
vapors  are  given  off  and  a  white  amorphous  sublimate  covers 
the  inside  of  the  tube,  which,  for  the  most  part,  does  not 
volatilize  when  reheated.  On  charcoal  the  assay  yields 
dense,  white,  inodorous  fumes. 

Tellurium.. — In  the  open  tube  a  white  or  grayish  subli- 
mate is  obtained,  which  may  be  fused  to  clear,  colorless 
drops.  On  charcoal  a  white  coating  is  produced,  and  the 
reducing  flame  is  colored  green. 

Siupltur. — All  sulphates  and  other  sulphur-bearing  min- 
erals, when  heated  on  charcoal  with  soda,  produce  a  dark, 
yellowish-brown  sulphide  of  sodium;  and  if  a  fragment  of 
this  is  moistened  and  placed  on  a  polished  plate  of  silver, 
it  turns  it  immediately  brownish  black,  or  black.  Pure 
soda,  and  a  flame  wholly  free  from  sulphur,  is  needed  for 
the  trial,  since  the  least  trace  of  sulphur  in  either  vitiates 
the  result.  Many  sulphides  give  fumes  of  sulphur  on  char- 
coal. The  higher  sulphides  afford  these  fumes  in  a  closed 
tube.  The  others  afford  fumes  of  sulphurous  acid  in  an 
open  tube,  which  redden  a  moistened  blue  litmus  paper 
placed  in  the  upper  end  of  the  tube. 

Selenium. — Selenium  and  many  selenides  afford  a  steel- 
gray  sublimate  in  an  open  tube,  which  at  the  upper  edge 
appears  red.  On  charcoal  brown  fumes  are  given  off  with 
an  odor  like  that  of  decaying  horse-radish. 

Chlorides. — If  a  bead  of  borax  be  saturated  with  copper 
oxide,  and  then  dipped  into  the  powder  of  a  substance 
which  ib  to  be  tested  for  chlorine,  a  chloride  of  copper  is 
formed  which  imparts  an  azure-blue  color  to  the  flame  if 
any  chlorine  is  present.  If  dissolved  in  water  or  nitric 
acid  a  little  silver  nitrate  produces  a  dense  white  precipi- 
tate of  silver  chloride. 

Nitrates. — A  nitrate,  if  fused  on  charcoal,  will  deflagrate 


102  CHEMICAL   PROPERTIES   OF   MINERALS. 

with  brilliancy,  owing  to  the  decomposition  of  the  nitrate 
and  the  union  of  its  oxygen  with  the  carbon. 

Phosphates. — Phosphates  give  a  dirty  green  color  to  the 
blowpipe  flame.  The  color  is  more  distinct  if  the  sub- 
stance is  first  moistened  with  sulphuric  acid.  If  a  phos- 
phate is  pulverized  and  heated  in  a  closed  glass  tube  with 
some  bits  of  magnesium  wire,  the  phosphoric  acid  is  re- 
duced; and  when  the  fusion  is  moistened  with  water  the 
very  disagreeable  odor  of  phosphuretted  hydrogen  is  ob- 
tained. 

For  a  full  account  of  blowpipe  reactions  recourse  should 
be  had  to.  a  treatise  on  the  blowpipe.  The  best  American 
works  on  the  subject  are  Prof.  G-.  J.  Brush's  ' '  Manual  of 
Determinative  Mineralogy,  with  an  Introduction  on  Blow- 
pipe Analysis,"  and  H.  B.  Cornwall's  "  Manual  of  Blow- 
pipe Analysis." 

In  the  description  of  species  beyond,  the  following  abbre- 
viations are  used  in  speaking  of  blowpipe  reactions: 

B.B.  =  before  the  blowpipe;  O.F.  =  oxidizing  flame; 
R.F.=  reducing  flame. 


CLASSIFICATION.  103 


IV.  DESCRIPTIONS  OF  MINERALS. 

CLASSIFICATION. 

SOME  of  the  prominent  points  in  the  classification  of 
minerals  adopted  in  the  following  pages  are  given  in  con- 
nection with  the  remarks  on  chemical  composition,  page 
79. 

Many  instructors  in  the  science,  and  most  of  those  who 
consult  a  work  on  Mineralogy  for  practical  purposes,  pre- 
fer an  arrangement  of  the  ores  which  groups  them  under 
the  head  of  the  metal  prominent  in  their  constitution. 
The  method  of  grouping  mineral  species  according  to  the 
basic  element  has  therefore  been  here,  to  a  large  extent, 
followed.  An  exception  has  been  made  in  the  case  of  the 
silicates,  because  it  is  with  them  almost  impracticable,  on 
account  of  the  number  of  basic  elements  they  often  con- 
tain ;  and,  moreover,  not  more  than  half  a  dozen  useful 
ores  exist  among  them.  The  silicates  therefore,  which  in- 
clude the  larger  part  of  all  minerals,  make  together  one  of 
the  grand  divisions  in  the  classification,  and  they  are  pre- 
sented according  to  their  natural  groups,  in  the  same  order 
as  in  the  larger  mineralogy. 

The  prominent  subdivisions  in  the  classification  are  as 
follows ; 

I.  THE  ACIDIC  DIVISION,  including  the  acidic  elements 
occurring  native,  and  the  native  compounds  of  the  acidic 
elements  with  one  another. 

II.  THE  BASIC  DIVISION,  including  the  basic  elements 
occurring  native,  and  the  native  binary  and  ternary  com- 
pounds of  the  basic  elements — the  silicates  excepted. 

III.  SILICA  and  the  SILICATES. 

IV.  THE   HYDROCARBON   COMPOUNDS,  including  min- 
eral oils,  resins,  wax,  and  coals. 

The  following  are  the  chief  subdivisions  under  these 
heads : 

I.  ACIDIC  DIVISION. 

1.  Sulphur  Group. — The  chief  oxide  a  trioxide,  its  for- 
mula BO,.  Includes  Sulphur  and  sulphur  oxides;  Tel- 


104  DESCRIPTIONS   OF   MINERALS. 

lurium  and  tellurium  oxides;  Molybdenum  sulphide  and 
oxide ;  Tungsten  oxide. 

2.  Boron   Group. — The  chief  oxide   a  trioxide,  its  for- 
mula B203.     Includes  compounds  of  Boron  with  oxygen. 

3.  Arsenic   Group. — The   chief  oxide   a  pentoxide,  its 
formula    E205.     Includes  Arsenic  and  arsenic  sulphides 
and  oxides  ;  Antimony  and  antimony  sulphide,  arsenide  and 
oxides;  Bismuth  and  bismuth  sulphide,  telluride  and  oxide. 

4.  Carbon  Group. — The  chief  oxide  a  dioxide,  its  for- 
mula E02.     Includes   Carbon   (Diamond,  Graphite)   and 
carbon  dioxide.     (Quartz,  Si02,   belongs  here  chemically, 
but  is  placed  with  the  Silicates.) 

II.  BASIC  DIVISION. 

Gold  ;  Silver  ;  Platinum  and  Iridium ;  Palladium  ;  Quick- 
silver ;  Copper  ;  Lead  ;  Zinc ;  Cadmium  ;  Tin ;  Titanium; 
Cobalt  and  Nickel ;  Uranium  ;  Iron  ;  Manganese ;  Alu- 
minium ;  Cerium,  Yttrium,  Lanthanum,  Didymium  and 
Erbium  ;  Magnesium ;  Calcium  ;  Barium  and  Strontium  ; 
Potassium  and  Sodium  ;  Ammonium  ;  Hydrogen. 

III.  SILICA  AND  SILICATES. 

1.  Silica. 

2.  Anhydrous  Silicates. 

1.  Bisilicates. 

2.  Unisilicates. 

3.  Subsilicates. 

3.  Hydrous  Silicates. 

1.  General  section  of  Hydrous  Silicates. 

2.  Zeolite  section. 

3.  Margarophyllite  section. 

IV.  HYDROCARBON  COMPOUNDS. 

1.  Oils,  Resins,  Wax. 

2.  Asphaltum,  Coals. 

GENERAL  REMARKS  ON  OIWES. 

An  ore,  in  the  mineralogical  sense  of  the  word,  is  a 
mineral  compound  in  which  a  metal  is  a  prominent  constit- 
uent. In  the  miner's  use  of  the  term  it  is  a  mineral  sub- 
stance that  yields,  by  metallurgical  treatment,  a  valuable 


GENERAL   REMARKS   ON   ORES.  105 

metal,  and  especially  when  it  profitably  yields  such  a 
metal.  In  the  former  sense,  galena,  the  common  ore  of 
lead,  is,  if  it  contains  a  little  silver,  an  argentiferous  lead- 
ore  ;  while,  in  the  latter,  if  there  is  silver  enough  to  make 
its  extraction  profitable,  it  is  a  silver-ore.  Further  than 
this,  where  a  native  metal,  or  other  valuable  metallic  min- 
eral, is  distributed  intimately  through  the  gangue,  the 
mineral  and  gangue  together  are  often  called  the  ore  of  the 
metal  it  produces. 

We  have  beyond  to  do  with  ores  only  in  the  mineralogi- 
cal  sense. 

Ores  are  compounds  of  the  metals,  not  metals  in  the 
native  state.  The  more  common  kinds  are  compounds  of 
the  metals  with  Sulphur  (sulphides) ;  with  Arsenic  (arsen- 
nides) ;  with  Sulphur  and  Arsenic  (sulph-arsenides) ;  with 
sulphur  in  ternary  combination  along  with  arsenic,  anti- 
mony or  bismuth  (making  compounds  called  sulph-arse- 
nites,  sulph-antimonites,  sulpho-bismutites) ;  with  Selenium 
(selenides)  ;  with  Tellurium  (tellurides) ;  'with  Oxygen 
(oxides)  ;  with  Chlorine,  Iodine,  or  Bromine  (chlorides, 
iodides,  or  bromides)  ;  with  oxygen  in  ternary  combina- 
tion with  carbon  (making  carbonates)  ;  with  Sulphur  (mak- 
ing sulphates)  ;  with  Arsenic  (making  arsenates) ;  with 
Phosphorus  (making  phosphates)  ;  with  Silicon  (making 
silicates). 

Gold  and  platinum  are,  with  rare  exceptions,  found  only 
native,  or  intimately  mixed  in  essentially  the  pure  state 
with  some  metallic  minerals.  Tellurium  is  the  only  acidic 
element  that  occurs  combined  with  gold  in  nature. 

Silver  is  found  in  the  state  of-  sulphide,  antimonide, 
selenide,  telluride,  sulph-arsenites  and  sulph-antimonites, 
but  never  as  oxide  or  in  oxygen  ternary  compounds. 

Quicksilver  occurs  in  the  state  of  sulphide  (the  common 
ore)  ;  also  in  that  of  selenide  and  sulph-arsenites. 

Copper  and  lead  occur  in  the  state  of  sulphides  (common 
ores),  and  also  in  all  the  binary  and  ternary  states  men- 
tioned above. 

Zinc  is  known  in  the  state  of  sulphide  (very  common), 
oxide,  carbonate,  sulphate,  silicate  (all,  excepting  the 
sulphate,  valuable  as  ores)  ;  and  Cadmium  in  that  of  sul- 
phide only. 

Tin  occurs  in  the  state  of  oxide  (the  common  ore)  and 
sulphide, 


106 


DESCRIPTIONS   OF   MINERALS. 


Cobalt  and  Nickel  occur  in  the  states  of  sulphide,  arse- 
nide, sulph-arsenides,  antimonide,  oxide,  sulphate,  arsenate, 
carbonate;  and  nickel  in  that  also  of  a  silicate. 

Iron  occurs  in  the  state  of  sulphide  (very  common,  but 
not  useful  as  an  ore  of  iron);  of  arsenide,  sulph-arsenide; 
of  oxide  (the  common  ores  of  iron);  carbonate  (useful  ore), 
sulphate,  arsenate,  phosphate,  silicate. 

Manganese  occurs  in  the  state  of  sulphide  (rare),  arse- 
nide (rare),  oxide  (the  common  ores),  carbonate,  sulphate, 
phosphate,  silicate. 


I.     MINERALS     CONSISTING    OF     THE    ACIDIC 
ELEMENTS. 

Oxygen  might  properly  be  included  in  this  section,  since 
it  occurs  native  in  the  atmosphere  mixed  with  nitrogen, 
constituting  81  per  cent  of  it.  But  this  mention  of  it  is 
all  that  is  necessary.  The  ternary  compounds,  in  which, 
as  in  sulphuric  acid,  hydrogen  is  the  basic  element,  are 
here  included.  Chlorine,  bromine,  and  iodine  do  not  occur 
native,  and  neither  do  their  oxides,  nor  any  compounds 
with  acidic  elements,  and  hence  these  elements  are  not 
represented  under  this  division.  The  same  is  true  of 
selenium  and  chromium  of  the  sulphur  group,  and  of  vana- 
dium, tantalum,  and  niobium  of  the  arsenic  group. 


f. 


1.    SULPHUR  GROUP. 
Native  Sulphur. 

Orthorhombic.  In  acute  octahedrons,  and  secondaries 
to  this  form,  with  imperfect  octahedral  cleavage;  lAl 
(in  same  pyramid)  =  106°  25'  and  85°  07';  lAl  (over 
base)  —  143°  23'.  Also  massive. 

Color  and  streak  sulphur-yellow, 
sometimes  orange -yellow.  Lustre 
resinous.  Transparent  to  translu- 
cent. Brittle.  H.  =  1.5  —  2.5. 
G.  =  2.07.  Burns  with  a  blue  flame 
and  sulphurous  odor.  In  a  closed 
tube  wholly  volatilized  and  redepos- 
ited  on  the  walls  of  the  tube. 

Native  sulphur  is  often  contaminated  with  clay  or  bitu- 


MINERALS   CONSISTING   OF  THE   ACIDIC    ELEMENTS.    10? 

men.  Sometimes  contains  selenium,  and  has  then  an 
orange-yellow  color. 

Diff.  It  is  easily  distinguished  by  its  burning  with  a  blue 
flame,  and  the  sulphur  odor  then  afforded. 

Obs.  The  great  repositories  of  sulphur  are  either  beds  of 
gypsum  and  the  associate  rocks,  or  the  regions  of  active  or 
extinct  volcanoes.  In  the  valley  of  Noto  and  Mazzaro  in 
Sicily,  at  Conil  near  Cadiz  in  Spain,  Bex  in  Switzerland, 
and  Cracow  in  Poland,  it  occurs  in  the  former  situation. 
Sicily  and  the  neighboring  volcanic  islands,  Vesuvius  and 
the  Solfatara  in  its  vicinity,  Iceland,  Teneriife,  Java,  Ha- 
waii, New  Zealand,  Deception  Island,  and  most  active  vol- 
canic regions,  aiford  more  or  less  sulphur. 

On  the  Potomac,  twenty-five  miles  above  Washington, 
sulphur  has  been  found  associated  with  calcite  in  a  gray 
compact  limestone;  sparingly  about  springs  where  hydrogen 
sulphide  is  evolved,  in  New  York  and  elsewhere;  in  cavities 
where  iron  sulphides  have  decomposed,  and  in  many  coal- 
mines. Abundant  near  Clear  Lake,  in  California;  Inferno, 
Humboldt  County,  and  Rabbit  Hole  Mines,  Nevada;  near 
Evanston,  Wyoming;  in  Utah,  Idaho,  etc. 

The  native  sulphur  of  commerce  is  brought  largely  from 
Sicily,  where  it  occurs  in  beds  along  the  central  part  of  the 
south  coast  and  to  some  distance  inland.  It  undergoes 
rough  purification  by  fusion  before  exportation,  which 
separates  the  earth  and  clay  with  which  it  occurs. 

Sulphur  when  cooled  from  fusion,  or  above  23^°  F.,  crys- 
tallizes in  oblique  rhombic  prisms.  When  poured  into 
water  at  a  temperature  above  300°  F.  it  acquires  the  con- 
sistency of  soft  wax,  and  is  used  to  take  impressions  of 
gems,  medals,  etc.,  which  harden  as  the  sulphur  cools. 
The  uses  of  sulphur  for  gunpowder,  bleaching,  the  manu- 
facture of  sulphuric  acid  (which  is  the  chief  use),  and  also 
in  medicines,  are  well  known.  Sulphur  occurs  in  various 
ores  as  sulphides  and  sulphates,  Among  the  sulphides  are 
pyrite,  marcasite  and  pyr^hotite,  iron  sulphides;  galena,  a 
lead  sulphide,  the  common  ore  of  lead;  clialcopyrite,  or 
yellow  copper-ore,  a  copper  and  iron  sulphide;  cinnabar ,  a 
mercury  sulphide;  ar gentile,  a  silver  sulphide,  etc. 

Sulphuric  and  Sulphurous  Acids. 

Sulphuric  acid  is  occasionally  met  with  around  volca- 
noes, and  it  is  also  formed  from  the  decomposition  of  hy- 
drogen sulphide  about  sulphur  springs. 


108  DESCRIPTIONS   OF   MINERALS. 

It  is  intensely  acid.  Composition,  Sulphur  trioxide 
(SOS)  81. 6,  water  18.4  =  100,,  it  being  chemically  hydrogen 
sulphate.  Occurs  in  the  waters  of  Rio  Vinagre,  South 
America;  in  Java;  in  Genesee  Co.,  N.  Y.,  at  Tuscarora; 
St.  Davids,  and  elsewhere,  Canada  West. 

Manufactured  from  sulphur,  and  also  from  the  common 
sulphides,  especially  pyrite. 

Sulphurous  acid,  or  sulphur  dioxide  (SOJ,  is  produced 
when  sulphur  burns,  and  causes  the  odor  perceived  during 
the  combustion  of  mineral  coal.  Common  about  active 
volcanoes.  It  destroys  life  and  extinguishes  combustion. 
Composition,  Sulphur  50.00,  oxygen  50.00. 

Native  Tellurium. 

Ehombohedral;  R  A  R  =  86°  57'.  Occurs  sometimes 
in  six-sided  prisms  with  perfect  lateral  cleavage;  but  is 
commonly  granular  massive.  Color  and  streak  tin-white. 
Brittle.  H.  =  2-2.5.  G.  =  6.1-6.3. 

Sometimes  contains*  a  little  iron,  and  also  a  trace  of 
gold.  In  an  open  tube,  B.  B.  yields  a  white  inodorous  sub- 
limate, which  may  be  fused  to  colorless  transparent  drops; 
and  on  charcoal  fuses  and  volatilizes,  tinging  the  flame 
green,  and  covering  the  charcoal  with  white  tellurium  di- 
oxide. 

Obs.  Occurs  in  Hungary  and  Transylvania;  also,  Boul- 
der Co.,  Colorado,  at  the  Red  Cloud  Mine;  in  Magnolia 
District  at  the  Keystone,  Dun  River,  and  other  mines;  in 
the  Ballerat  District  at  Smuggler  Mine;  in  Central  Dis- 
trict at  the  John  Jay  Mine,  where  masses  of  25  pounds 
weight  are  reported  to  have  been  found.  Lionite  is  an  im- 
pure variety  from  Mountain  Lion  Mine. 

Tellurium  is  also  a  constituent  of  ores  of  gold,  silver,  mercury, 
bismuth,  and  lead,  forming  with  the  metals  tellurides  (pp.  102,  116, 
117,  118;,  129,  147);  petzite  and  sylvanite  (p.  118)  are  the  most  abun- 
dant, and  large  quantities — from  Boulder  Co.,  Colorado,  chiefly — are 
smelted  for  gold  and  silver  at  Denver.  Tellurium  is  not  used  in  the 
arts. 

Tellurite  (Tellurous  acid},  TeO2.  The  Keystone,  Smuggler,  and 
John  Jay  Mines;  especially  the  last,  where  it  is  in  minute  white  cr 
yellowish  crystals  having  one  eminent  cleavage. 

Molybdenite. — Molybdenum  Sulphide. 

In  hexagonal  plates,  or  masses,  thin  foliated  like  graph- 
ite, and  resembling  that  mineral.  H.  =  1—1.5.  G.  — 


MINERALS   CONSISTING    OF   THE   ACIDIC    ELEMENTS.    109 

4.45-4  8.  Color  pure  lead-gray;  streak  the  same,  slightly 
inclined  to  green.  Thin  laminse  very  flexible;  not  elastic. 
Leaves  a  trace  on  paper,  like  graphite,  but  its  color  is 
slightly  different,  being  bluish-gray. 

Composition,  MoS2  =  Sulphur  41.0,  molybdenum  59.0 
=  100.  B.B.  infusible;  but  when  heated  on  charcoal, 
sulphur  fumes  are  given  off,  which  are  deposited  on  the 
coal.  Dissolves  in  nitric  acid,  excepting  a  gray  residue. 

Diff.  Resembles  graphite,  but  differs  in^  its  paler  color 
and  streak,  and  also  in  giving  fumes  of  sulphur  when 
heated,  as  well  as  by  its  solubility  in  nitric  acid. 

Obs.  Occurs  in  granite,  gneiss,  mica  schist,  and  allied 
rocks;  also  in  granular  limestone.  Found  in  Sweden;  at 
Arendal  in  Norway;  in  Saxony;  Bohemia;  Caldbeck  Fell 
in  Cumberland;  and  in  the  Cornish  mines. 

In  the  U.  S.  occurs  at  Blue  Hill  Bay,  Camdage  Farm, 
Brunswick,  and  Bowdoinham,  Me.;  at  Westmoreland, 
Landaff,  and  Franconia,  N.  H. ;  at  Shutesbury  and  Brim- 
field,  Mass. ;  at  Haddam  and  Saybrook,  Ct. ;  near  Warwick, 
N.  Y. ;  near  Franklin  Furnace,  N.  J. 

Molybdenum  does  not  occur  native.  Yellow  oxide  is  an 
occasional  result  of  its  alteration.  Occurs  combined  with 
lead  as  a  mplybdate  (page  151),  which  is  the  only  native 
salt  containing  it.  Named  from  the  Greek  molubdaina, 
meaning  mass  of  lead,  in  allusion  to  the  resemblance  of 
molybdenite  to  graphite. 

Tungstite  (Tungstic  ochre).  A  yellow  powder  or  incrustation  oc- 
curring with  wolfram,  and  a  result  of  its  decomposition.  Occasion- 
ally observed  at  Lane's  Mine,  Monroe,  Ct.  Meymacite;  hydrous  WO8. 

Besides  this  oxide  there  are  the  native  compounds,  iron  tungstate 
or  wolfram  (p.  200),  manganese  tungstate  (p.  200),  lead  tungstate  (p. 
66),  and  calcium  tungstate  (p.  232).  Tungsten  also  occurs  sparingly 
in  some  ores  of  niobium,  as  in  certain  varieties  of  the  minerals 
pyrochlore,  columbite,  and  yttro  columbite. 

2.  BORON  GROUP. 

In  Boron,  as  in  the  Sulphur  group,  the  most  prominent 
oxide  is  a  trioxide. 

Sassolite. — Boracic  Acid.     Sassolin. 

Occurs  in  small  scales,  white  or  yellowish.  Feel  smooth 
and  unctuous.  Taste  acidulous  and  a  little  saline  and  bit- 
ter. G.  =  1.48.  Composition,  H606Boa  =  Boron  triox- 
ide 56.4,  water  43.6.  It  is  strictly  hydrogen  lor  ate. 


110  DESCRIPTIONS   OF   MINERALS. 

Fuses  easily  in  the  flame  of  a  candle,  tinging  the  flame 
at  first  green. 

Found  at  the  crater  of  Vulcano,  and  also  at  Sasso  in 
Italy,  whence  it  was  called  Sassolin.  The  hot  vapors  of 
the  lagoons  of  Tuscany  afford  it  in  large  quantities.  The 
vapors  are  made  to  pass  through  water,  which  condenses 
them;  and  the  water  is  then  evaporated  by  the  steam  of 
the  springs,  and  boracic  acid  obtained  in  large  crystalline 
flakes.  It  still  requires  purification,  as  the  best  thus  pro- 
cured contains  but  50  per  cent  of  the  pure  acid.  Occurs 
also  in  the  waters  of  Lick  Springs,  Tehania  Co.,  and  Borax 
Lake,  Lake  Co.,  California,  where  it  was  first  observed, 
through  their  evaporation,  by  Dr.  J.  A.  Veatch,  in  1856. 
It  has  since  been  obtained  from  the  waters  of  Mono, 
Owens,  and  other  lakes.  It  exists  sparingly  in  the  waters 
of  the  ocean.  But  in  all  these  waters,  it  is  probably  in 
combination. 

Boron  occurs  usually  in  the  condition  of  magnesium,  calcium,  and 
sodium  borates  (pp.  225,  231,  246);  and  rarely  as  an  iron  borate  (p. 
182),  or  ammonium  borate  (p.  231).  It  also  occurs  in  the  silicates, 
tourmaline,  danburite,  axinite,  and  datolite,  in  which  it  is  easily  de- 
tected by  the  blowpipe  reaction  (p.  99).  The  borax  of  commerce 
(hydrous  sodium  borate)  is  derived  mostly  from  native  borax  (p.  99), 
but  also  from  the  sodium-calcium  borate  (ulexite)  and  to  some  extent 
from  sassolin. 

3.  THE  ARSENIC  GROUP. 

The  elements  of  the  Arsenic  group  occurring  among 
minerals  are  arsenic,  antimony,  bismuth,  phosphorus, 
nitrogen,  vanadium,  tantalum,  niobium.  Of  these,  ar- 
senic, antimony,  and  bismuth  occur  native,  and  as  sul- 
phides; also,  in  combination  with  other  metals,  constituting 
arsenides,  antimonides,  bismu tides;  and,  along  with  sul- 
phur also,  making  sulpharsenites,  sulphantimonites,  sulph- 
bismutites.  In  addition,  they  all,  excepting  bismuth,  en- 
ter into  the  constitution  of  a  series  of  native  ternary  oxygen 
compounds,  called,  severally,  arsenates,  antimonates,  phos- 
phates, nitrates,  vanadates,  tantalates,  niobates. 

The  chief  oxide  has  the  general  formula  R206. 

Native  Arsenic. 

Rhombohedral.  R  A  K  =  85°  41'.  Cleavage  basal,  im- 
•  perfect.  Also  massive,  columnar,  or  granular. 


MINERALS   CONSISTING    OF   THE   ACIDIC    ELEMENTS.    Ill 

Color  and  streak  tin-white,  but  usually  dark  grayish  from 
tarnish.  Brittle.  H.  =  3 -5.  G.  =  5-65-5-95. 

B.B.  volatilizes  readily  before  fusing,  with  the  odor  of 
garlic;  burns  with  a  pale  bluish  flame  when  heated  just 
below  redness. 

Obs.  Occurs  with  silver  and  lead  ores.  Found  in  con- 
siderable quantities  at  the  silver  mines  of  Freiberg  and 
Sehneeberg;  in  Bohemia;  the  Hartz;  at  Kapnik  in  tipper 
Hungary;  in  Siberia  in  large  masses,  and  elsewhere. 

In  the  U.  States  observed  sparingly  at  Haverhill  and 
Jackson,  1ST.  H. ;  at  Greenwood,  Me. 

Orpiment. — Yellow  Arsenic  Sulphide. 

Orthorhombic.  Cleavage  highly  perfect  in  one  direction. 
In  foliated  masses,  and  sometimes  in  prismatic  crystals. 
Color  and  streak  fine  yellow.  Lustre  brilliant  pearly,  or 
metallic  pearly,  on  the  face  of  cleavage.  Subtransparent 
to  translucent;  sectile.  H.  =  1*5-2.  G.  =  3*4-3-5. 

Composition.  As2  S3  =  Sulphur  39-0,  arsenic  61-0. 
Wholly  evaporates  before  the  blowpipe  with  an  alliaceous 
odor,  and  on  charcoal  burns  with  a  blue  flame. 

From  Hungary,  Koordistan  in  Turkey  in  Asia,  China, 
and  South  America.  Occurs  at  Edenville,  N".  Y.,  as  a  yel- 
low powder,  resulting  from  the  decomposition  of  arsenical 
iron;  Coyote  Dist.,  Iron  Co.,  Utah. 

Realgar.  The  arsenic  sulphide  As  S.  Color  fine  clear  red,  aurora- 
red  to  orange,  transparent  or  translucent;  H.=  1/5-2;  G.=  3 '35-3  65; 
Composition,  As  8  =  Sulphur  29'9,  arsenic  70'1  =  100.  B.B.  like 
the  preceding.  Hungary,  Bohemia,  Saxony,  the  Hartz,  Switzerland, 
and  Koordistan  in  Asiatic  Turkey.  Has  been  observed  in  the  lavas 
of  Vesuvius. 

Realgar  is  one  of  the  ingredients  of  white  Indian  fire,  often  used  ns 
a  signal  light.  Orpiment  is  a  coloring  ingredient  in  the  pigment  called 
king's  yellow,  in  which  it  is  mixed  with  arsenous  acid. 

Arsenolite.— White  Arsenic.     Arsenous  Acid. 

Isometric.  In  minute  capillary  crystals,  and  botryoidal 
or  stalactitic.  Color  white.  Soluble;  taste  astringent, 
sweetish.  H.  =  1-5.  G.  =  3-7. 

Composition.    As30?  =  Arsenic  75 '8,  oxygen  24-2  =  100. 

The  common  arsenic  of  the  shops.  Found  sparingly  na- 
tive, accompanying  ores  of  silver,  lead,  and  arsenic,  in  the 
Hartz,  Bohemia,  and  elsewhere.  A  well-known  poison. 

Claudetite  is  the  same  compound  in  orthorhombic  forms;  from  Por- 
tugal. 


112  DESCRIPTIONS   OF   MINERALS. 

General  Remarks. — Arsenic  is  obtained  for  commerce  chiefly  from 
arsenopyrite  (or  mispickel),  an  ironsulph-arsenide,  and  from  the  nickel 
and  cobalt  arsenides,  by  first  roasting  off  the  sulphur,  and  then  con- 
densing the  arsenic,  in  the  state  of  As2  O3  ("  arsenous  acid  ")  in  large 
chambers.  Arsenopyrite  is  used  for  making  the  oxide  at  the  Deloro 
mine  in  Ontario,  Canada,  where  200  tons  were  produced  in  1884.  To 
obtain  the  material  pure  it  is  usually  sublimed  again.  In  Devon  and 
Cornwall  the  arsenical  ores  occur  with  the  tin  ore,  and  a  large  amount 
of  white  arsenic  is  made.  The  metal  arsenic  forms  a  small  part  of 
some  alloys;  the  most  important  is  that  with  lead  for  shot-making. 
3,693,325  pounds  of  white  arsenic  were  imported  into  the  U.  States 
in  1884,  and  5,207,553  pounds  in  1883. 

Native  Antimony. 

Kliombohedral;  R/\  R  =  87°  35'.  Usually  massive,  with 
a  very  distinct  lamellar  structure;  sometimes  granular. 
Color  and  streak  tin-white.  Brittle.  H.  =  3-3*5.  G.  = 
6-6-6-75. 

Composition.  Pure  antimony,  often  with  a  little  silver, 
iron,  or  arsenic.  B.B.  on  charcoal  fuses  easily  and  passes 
off  in  white  fumes. 

Obs.  Occurs  in  veins  of  silver  and  other  ores  in  Dauphiny; 
Bohemia;  Sweden;  the  Hartz;  Mexico;  New  Brunswick. 

Stibnite.— Gray  Antimony.     Antimony  Sulphide. 

Orthorhombic;  /A  /  —  90°  26'.    In  right  rhombic  prisms, 
with  striated  lateral  faces.     Cleavage  in  the  direction  of 
the  shorter  diagonal,  highly  perfect.     Com- 
monly divergent  columnar  or  fibrous.     Some- 
times massive  granular. 

Color  and  streak  lead-gray;  liable  to  tarnish. 
Lustre  shining.  Brittle;  but  thin  laminae  a 
little  flexible.  Somewhat  sectile.  H.  =  2. 
G.  =  4-5-4-62. 

Composition.  SbaS3  =  Sulphur  28*2,  anti- 
mony 71-8.  Fuses  readily  in  the  flame  of  a 
candle.  B.B.  on  charcoal  it  is  absorbed,  giv- 
ing off  white  fumes  and  a  sulphur  odor. 

Diff.  Distinguished  by  its  extreme  fusibility 
and  its  vaporizing  before  the  blowpipe. 

Obs.  In  veins  with  ores  of  silver,  lead,  zinc,  or  iron,  and 
often  associated  with  barite,  spathic  iron,  or  quartz.  Oc- 
curs at  Felsobanya  and  Schemnitz  in  Hungary;  "Wolfsberg 
in  the  Hartz;  Briiunsdorf  near  Freiberg;  in  Auvergne; 
Cornwall;  Spain;  Portugal;  Tuscany,  Italy;  Borneo;  Bhi- 


MINERALS   CONSISTING    OF  THE   ACIDIC   ELEMENTS.    113 

koku,  S.  Japan,  in  magnificent  crystals;  N.  S.  Wales  and 
Victoria,  Australia. 

In  the  U.  States,  sparingly  at  Carmel,  Me.,  Lyme,  K".  H., 
and  at  <s  Soldier's  Delight,"  Md. ;  abundant  in  San  Emidio 
Canon,  Kern  Co.,  Cal.;  also  in  San  Bernardino,  Inyo, 
Mono,  Lake,  Tulare,  and  Monterey  Cos.,  Cal.;  in  Relief 
district,  Humboldt  Co. ,  Nev. ;  in  the  mines  of  Aurora,  Es- 
meralda  Co.,  Nev. ;  also  12  miles  south  of  Battle  Mountain, 
Nev.;  in  Utah,  in  Iron  Co.,  on  Coyote  creek,  abundant. 
Also  worked  in  !N".  Brunswick,  20  miles  west  of  Fredericton: 
in  Eawdon  township,  Hants  Co.,  N.  Scotia. 

Affords  the  most  of  the  antimony  of  commerce.  By  sim- 
ple fusion,  the  crude  antimony  of  the  shops  is  obtained, 
from  which  pure  antimony  and  its  pharmaceutical  prepara- 
tions are  made.  Antimony  constitutes  17.20  per  cent,  of 
type-metal,  10  to  16  per  cent,  of  Britannia  metal,  8.3  per 
cent,  of  Babbitt  metal,  and  about  7  of  pewter. 

Allemontite.  Arsenical  antimony,  Sba  As3.  Allcmont;  Bohemia; 
the  Hartz. 

Valentinite.  White  antimony  in  white,  grayish,  or  reddish  rectan- 
gular crystals,  "with  perfect  cleavage,  affording  a  rhombic  prism  of 
136°  58'.  Also  in  tabular  masses,  and  columnar  and  granular.  H.= 
2*5-3.  G.— 5'57.  Lustre  adamantine  to  pearly.  Composition,  Sba 
O3  =  Oxygen  16'44,  antimony  83'56  =  100.  Bohemia;  Hungary; 
Saxony;  Dauphiny;  Sonora,  Mexico. 

Senarmonite.     Same  as  Valentinite,  but  isometric. 

Kermesite  or  Bed  antimony.  An  antimony  oxide  and  sulphide,  in 
red  tufts  of  capillary  crystals;  lustre  adamantine.  Hungary,  Dau- 
phiny, Saxony,  the  Hartz. 

Cervantite.  Antimony  oxide,  Sb2  04,  resulting  from  the  decompo- 
sition of  stibnite. 

Livingstonite.  Like  stibnite,  but  contains  14  per  cent,  of  mercury 
and  has  a  red  streak.  Euitzuco  and  Guadalcazar,  Mexico. 

Native  Bismuth. 

Rhombohedral;  R/\R  =  %T  40'.  Cleavage  rhombo- 
hedral,  perfect.  Generally  massive,  with  distinct  cleavage; 
sometimes  granular. 

Color  and  streak  silver  white,  with  a  slight  tinge  of  red. 
Subject  to  tarnish.  Brittle  when  cold,  but  somewhat  mal- 
leable when  heated.  H.  =  2-2-5.  G.  =  9 '7-9 -8.  Fuses 
at  a  temperature  of  476°  F. 

Composition.  Pure  bismuth,  with  sometimes  a  trace  of 
arsenic,  sulphur,  or  tellurium.  B.B.  on  charcoal  vaporizes, 
and  leaves  a  yellow  coating  on  the  coal,  paler  on  cooling. 

Obs.  Abundant  with  ores  of  silver  and  cobalt  in  Saxony 
8 


114  DESCRIPTIONS   OF  MINERALS. 

and  Bohemia;  also  in  Cornwall  and  Cumberland,  England; 
in  Norway,  Sweden,  Chili,  and  Bolivia;  at  the  Balhannah 
mine,  in  S.  Australia,  with  copper  ore  and  gold.  At 
Schneeberg,  it  forms  arborescent  delineations  in  brown 
jasper. 

In  the  U.  States,  found  at  Lane's  and  Booth's  mine, 
Monroe,  Ct.,  with  tungsten,  galenite,  and  pyrite;  at  Brew- 
er's mine,  in  Chesterfield  district,  S.  C.;  in  Colorado;  12 
miles  west  of  Beaver  City,  Utah. 

Bismuthiniie.  A  bismuth  sulphide,  Bi2  S3,  in  acicular  crystals  of  a 
lead-gray  color;  also  massive.  Five  miles  N.  of*  Golden,  Col.;  in 
Beaver  Co.,  Utah  ;  and  elsewhere. 

Guanajuatits.  A  bismuth  selenide,  called  blBofremelite.  Silaonite, 
from  the  same  locality,  is  a  mixture.  Guanajuato,  Mexico. 

Tetradymite.— Bismuth  Telluride. 

Hexagonal;  R  A  R  =  81°  2'.  Crystals  often  tabular,  with 
a  very  perfect  basal  cleavage.  Also  massive,  and  foliated 
or  granular.  Laminae  flexible.  Lustre  splendent  metallic. 
Color  pale  steel-gray,  a  little  sectile.  H.  =  1  -5 — 2.  G.  = 
7-2— 7-9:  f  Soils  paper. 

Composition.  Consists  of  bismuth  and  tellurium,  with 
sometimes  sulphur  and  selenium.  Affords  for  the  most 
part  the  formula  Bi2  (Te,  S)3.  A  variety  from  Dahlonega, 
Ga.,  gave  Tellurium  48'1,  bismuth  51-9  =  Bi,Tes;  G.= 
7*642.  Joseite  is  a  bismuth  telluride  from  Brazil,  in  which 
half  the  bismuth  is  replaced  by  sulphur ;  WeJirlitfi  is  an- 
other containing  sulphur,  from  Deutsch  Pilsen,  Hungary, 
having  G.=  8  -44. 

Obs.  Found  with  gold  in  Virginia,  N.  Carolina,  and 
Ga. ;  Highland,  Montana;  Red  Cloud  Mine,  Col.;  Mont- 
gomery Mine,  Arizona. 

Bismite  (Bismuth  ochre).  An  impure  oxide ;  grayish  to  greenish 
and  yellowish  white  ;  massive  or  earthy.  Found  with  native  bismuth. 
Bolimte  is  a  related  mineral. 

Daubreite.     A  bismuth  oxychloride.     Bolivia. 

Bismiititc.  Bismuth  carbonate;  pale  yellow  to  green,  G.— 7 — 7'5. 
Found  with  other  bismuth  ores.  WaltJierite  and  Bismutosphcerite  be- 
long here.  Montanite  is  bismuth  tellurate;  Montana;  N.  Car. 

PucJierite.  Bismuth  vanadate ;  orthorhombic  ;  reddish  brown. 
Schneeberg,  Saxony.  Atelestite,  Rhagite,  bismuth  arsenate. 

Tazniie.     Supposed  to  be  a  bismuth  arsenio  antimonate.     Peru. 

For  the  sulpho-bismuthides,  see  pp.  00,  00;  and  for  a  silicate,  p.  0. 
,      General  Remarks.— The  metal  bismuth  is  obtained  mostly  from  na- 
/  tive  bismuth,  and  the  most  valuable  mines  are  in  Saxony,  Hungary, 
Baden,  Cornwall,  and  Australia.    Besides  the  above  ores,  there  are 


MINERALS  CONSISTING   OF  THE   ACIDIC   ELEMENTS.    115 

also  others  in  which  the  metal  is  combined  with  silver,  lead,  and 
'  '  :el  (pp.  134,  183). 

4.  CARBON  GROUP. 

The  Carbon  group  in  chemistry  comprises  carbon  and 
silicon,  in  which  the  formula  for  the  most  prominent  oxide 
is  R02.  Only  carbon  occurs  native. 

Carbon  occurs  crystallized  in  the  diamond  and  graphite; 
as  oxides,  in  carbon  oxide,  and  carbon  dioxide  (ordinarily 
called  carbonic  acid);  combined  with  hydrogen,  or  hydrogen 
and  oxygen,  in  bitumen,  mineral  oils,  amber,  and  a  num- 
ber of  native  mineral  resins,  and  mineral  wax;  and  as  the 
chief  constituent  of  mineral  coal,  in  which  it  is  combined 
with  more  or  less  of  hydrogen  and  oxygen  and  usually  some 
nitrogen. 

Diamond. 

Isometric.  In  octahedrons,  dodecahedrons  and  more 
complex  forms  ;  faces  often  curved.  Cleavage  octahedral ; 
perfect. 

1.  2. 


Color  white,  or  colorless ;  also  yellowish,  red,  orange, 
green,  blue,  brown  or  black.  Lustre  adamantine.  Trans- 
parent ;  translucent  when  dark-colored.  H.  =  10.  G.  = 
3-48-3-55. 

Composition.  Pure  carbon.  Burns  and  is  consumed  at  a 
high  temperature,  producing  carbonic-acid  gas.  Exhibits 
vitreous  electricity  when  rubbed.  Some  specimens  exposed 
to  the  sun  for  a  while  give  out  light  when  carried  to  a  dark 
place.  Strongly  refracts  and  disperses  light. 

Diff.  Distinguished  by  the  hardness;  brilliant  reflection 
of  light  and  adamantine  lustre;  vitreous  electricity  when 
rubbed,  which  is  not  afforded  by  other  gems  unless  they  are 


116  ,     DESCRIPTIONS   OF   MINERALS. 

polished  ;  and,  to  the  practised  ear,  by  means  of  the  sound 
when  rubbed  together. 

Obs.  Coarse  diamonds,  unfit  for  jewelry,  are  called  bort, 
and  the  kind  in  black  pebbles,  or  masses,  from  Brazil,  car- 
bonado. The  latter  occur  sometimes  in  pieces  1000  carats 
in  weight;  they  have  G.  —  3  to  3'42.  Another  kind  is  much 
like  anthracite,  G.  =1-66,  although  as  hard  as  diamond 
crystals;  it  is  in  globules  or  mammillary  masses,  often  partly 
made  up  of  concentric  layers. 

Diamonds  occur  in  India,  in  the  district  between  Golconda 
and  Masulipatam,  and  near  Parma,  in  Bundelcund,  where 
some  of  the  largest  have  been  found;  also  on  the  Mahanud- 
dy,  in  Ellore.  In  Borneo,  they  are  obtained  on  the  west 
side  of  the  Ratoos  Mountain,  with  gold  and  platina.  The 
Brazilian  mines  were  first  discovered  in  1728,  in  the  district 
of  Serra  do  Frio,  to  the  north  of  Eio  de  Janeiro;  the  most 
celebrated  are  on  the  river  Jequitinhonha,  which  is  called 
the  Diamond  River,  and  the  Rio  Pardo;  seventy  to  seventy- 
five  thousand  carats  are  exported  annually  from  these  re- 
gions. In  the  Urals  of  Russia  they  had  not  been  detected 
till  July,  1829,  when  Humboldt  and  Rose  were  on  their 
journey  to  Siberia.  The  river  Gunil,  in  the  province  of 
Constantine,  in  Africa,  is  reported  to  have  afforded  some 
diamonds. 

In  South  Africa,  where  they  were  first  discovered  in  1867, 
they  occur  in  the  gravel  of  the  Vaal  River  and  in  the 
Orange  River  country.  In  Australia,  on  the  Macquarie, 
and  elsewhere. 

In  the  United  States,  the  diamond  has  been  met  with  in 
Rutherford,  Lincoln,  Mecklenburg,  Franklin,  and  other 
counties,  N.  C.;  Hall  Co.,  Ga.;  Manchester,  opposite  Rich- 
mond, Ya.,  a  crystal  weighing  24f  carats  before  cutting, 
and  nearly  half  that  after  cutting;  also  in  Cherokee  Flat, 
and  other  places  in  Butte  Co.,  Forest  Hill'  in  El  Dorado 
Co.  (one  weighing  nearly  1^  carats),  Fiddletown  in  Amador 
Co.,  San  Juan  Co.  in  Colorado;  in  Nevada  Co.,  Cal.;  and 
with  platinum  on  the  coast  of  Southern  Oregon;  and  one 
fine  stone  of  f  ths  carat,  near  San  Francisco.  It  has  been 
reported  from  Idaho,  Arizona,  Montana;  also  from  the 
drift  in  Waukesha  Co.,  Wis.,  one  of  15  carats. 

The  original  rock  in  Brazil  appears  to  be  either  a  lami- 
nated quartzyte  (itacolumyte),  or  a  ferruginous  quartzose 
conglomerate.  The  itacolumyte  occurs  in  the  Urals,  and 


I    If 


MINERALS   CONSISTING    OF   THE   ACIDIC   ELEMENTS.    117 

diamonds  have  been  found  in  it;  and  it  is  also  abundant 
in  Georgia  and  North  Carolina.  According  to  Genth,  the 
auriferous  sands  in  N.  Carolina,  affording  the  diamond  with 
zircons,  monazite,  etc.,  are  the  debris  of  gneiss  and  mica 
schist,  and  some  graphite  is  always  present.  In  India, 
the  rock  is  a  quartzose  conglomerate.  The  origin  of  the 
diamond  has  been  a  subject  of  speculation,  and  it  is  the 
prevalent  opinion  that  the  carbon,  like  that  of  coal,  much 

fraphite,  and  mineral  oil,  is  of  vegetable  or  animal  origin, 
ome  crystals  have  been  found  with  black  uncrystallized 
particles  or  seams  within,  looking  like  coal ;  and  this  fact 
has  been  supposed  to  indicate  such  an  origin. 

Diamonds,  with  few  exceptions,  are  obtained  from  allu- 
vial washings.  In  Brazil,  the  sands  and  pebbles  of  the 
diamond  rivers  and  brooks  (the  waters  of  which  are  drawn 
off  in  the  dry  season  to  allow  of  the  work)  are  collected  and 
washed  under  a  shed,  by  a  stream  of  water  passing  through 
a  succession  of  boxes.  A  washer  stands  by  each  box,  and 
inspectors  are  stationed  at  intervals. 

Diamonds  are  valued  according  to  their  color,  transpa- 
rency, and  size.  The  rose  diamond  is  more  valuable  than 
the  pure  white,  owing  to  the  great  beauty  of  its  color  and 
its  rarity.  The  green  diamond  is  much  esteemed  on  ac- 
count of  its  color.  The  blue  is  prized  only  for  its  rarity,  as 
the  color  is  seldom  pure.  The  black  diamond,  which  is 
uncommonly  rare  and  without  beauty,  is  highly  prized  by 
collectors.  The  brown,  gray,  and  yellow  varieties  are  of 
much  less  value  than  the  pure  white  or  limpid  diamond. 

The  largest  diamond  on  record  (doubtful)  is  that  men- 
tioned by  Tavernier  as  in  the  possession  of  the  Great  Mogul. 
It  weighed  originally  900  carats,  or  2769-3  grains,  was  re- 
duced by  cutting  to  861  grains,  had  the  form  and  size  of  half 
of  a  hen's  egg,  and  is  said  to  have  been  found  in  1550,  in 
the  mine  of  Colone.  The  diamond  which  formed  the  eye 
of  a  Braminican  idol,  and  was  purchased  bjr  the  Empress 
Catherine  II.  of  Russia  from  a  French  grenadier  who  had 
stolen  it,  weighs  194f  carats,  and  is  as  large  as  a  pigeon's 
egg.  The  Austrian  crown  has  a  diamond  weighing  139£ 
carats.  The  Pitt  or  Eegent  diamond  is  of  less  size,  it 
weighing  but  136*25  carats,  or  419^  grains;  but  on  account 
of  its  unblemished  transparency  and  color  it  is  considered 
the  most  splendid  of  Indian  diamonds.  It  was  sold  to  the 
Duke  of  Orleans  by  Mr.  Pitt,  an  English  gentleman,  who 


118  DESCRIPTIONS   OF   MINERALS. 

was  governor  of  Bencoolen,  in  Sumatra,  for  £130,000.  It  is 
cut  in  the  form  of  a  brilliant,  and  is  estimated  at  £125,000. 
The  Kajah  of  Mattan  has  in  his  possession  a  diamond  from 
Borneo,  weighing  367  carats.  The  Koh-i-noor,  on  its  arrival 
in  England,  weighed  186-016  carats.*  It  is  said  by  Taver- 
nier  to  have  originally  weighed  787-J  carats.  It  has  since 
been  recut  and  reduced  one  third  in  weight. 

In  the  Dresden  Treasury  there  is  an  emerald-green  dia- 
mond weighing  31|  carats.  The  Hope  diamond,  weighing 
44 fa  carats,  has  a  beautiful  sapphire-blue  color. 

The  diamonds  of  Brazil  are  seldom  large.  Maure  men- 
tions one  of  120  carats,  but  they  rarely  exceed  18  or  20. 
One  weighing  254|-  carats,  called  the  "Star  of  the  South" 
was  found  in  1854. 

Of  South  African  diamonds,  the  "  Schreiner"  weighed, 
in  its  rough  state,  308  carats;  and  the  "Stewart,"  which 
has  a  light  straw  color,  288*35  carats;  and  one  of  475  carats 
was  reported  in  1885  as  about  to  be  cut  at  Amsterdam. 
The  diamonds  of  South  Africa  are  mostly  (( off  color";  about 
10  per  cent,  are  of  first  quality;  15,  2d;  20,  3d;  and  55  per 
cent,  are  bort  (W.  J.  Morton).  The  "  Star  of  South  Africa/' 
of  pure  water,  weighed  83 '5  carats.  Some  crystals  crack 
to  pieces  after  being  exposed  to  the  air  awhile. 

The  diamond  is  cut  by  taking  advantage  of  its  cleavage, 
and  also  by  abrasion  with  its  own  powrder.  The  flaws  are 
sometimes  removed  by  cleaving  it.  Afterwards  the  crystal 
is  fixed  to  the  end  of  a  stick  of  soft  solder  when  the  solder 
is  in  a  half -melted  state,  leaving  the  part  projecting  which 
is  to  be  cut.  A  circular  plate  of  soft  iron  is  then  charged 
with  the  powder  of  the  diamond,  and  this,  by  its  revolution, 
grinds  and  polishes  the  stone.  *  By  changing  the  position, 
other  facets  are  added  in  succession  till  the  required  form 
is  obtained.  Diamonds  were  first  cut  in  Europe,  in  1456, 
by  Louis  Berghem,  a  citizen  of  Bruges;  but  in  China  and 
India  the  art  of  cutting  appears  to  have  been  known  at  a 
very  early  period. 

By  the  above  process,  diamonds  are  cut  into  brilliant,  rose, 
and  table  diamonds.  The  brilliant  has  a  crown  or  upper 
part,  consisting  of  a  large  central  eight-sided  facet,  and  a 

*  A  carat  is  a  conventional  weight.  In  England  it  equals  3  174  grains  troy. 
Schrauf  makes  it  vary  in  Europe  from  197'20  mgr.  to  206-13.  and  in  London  205-409. 
The  term  carat  is  derived  from  the  name  of  a  bean  in  Africa,  which,  in  a  dried 
state,  has  long  been  used  in  that  country  for  weighing  gold.  These  beans  were 
early  carried  to  India,  and  were  employed  there  for  weighing  diamonds. 


MINERALS   CONSISTING    OF   THE   ACIDIC    ELEMENTS.    119 

series  of  facets  around  it;  and  a  collet,  or  lower  part,  of  py- 
ramidal shape,  consisting  of  a  series  of  facets,  with  a  smaller 
series  near  the  base  of  the  crown.  The  depth  of  a  brilliant 
is  nearly  equal  to  its  breadth,  and  it  therefore  requires  a 
thick  stone.  Thinner  stones,  in  proportion  to  the  breadth, 
are  cut  into  rose  and  table  diamonds.  The  surface  of  the 
rose  diamond  consists  of  a  central  eight-sided  facet  of  small 
size,  ei^ht  triangles,  one  corresponding  to  each  side  of  the 
table,  eight  trapeziums  next,  and  then  a  series  of  sixteen 
triangles.  The  collet  side  consists  of  a  minute  central  octa- 
gon, surrounded  by  eight  trapeziums,  corresponding  to  the 
angles  of  the  octagon,  each  of  which  trapeziums  is  subdi- 
vided by  a  salient  angle  into  one  irregular  pentagon  and 
two  triangles.  The  table  is  the  least  beautiful  mode  of  cut- 
ting, and  is  used  for  such  fragments  as  are  quite  thin  in 
proportion  to  the  breadth.  It  has  a  square  central  facet, 
surrounded  by  two  or  more  series  of  four-sided  facets,  cor- 
responding to  the  sides  of  the  square. 

Diamonds  have  also  been  cut  with  figures  upon  them. 
As  early  as  1500,  Charadossa  cut  the  figure  of  one  of  the 
Fathers  of  the  church  on  a  diamond,  for  Pope  Julius  II. 

Diamonds  are  employed  for  cutting  glass;  and  for  this 
purpose  only  the  natural  edges  of  crystals  can  be  used,  and 
those  with  curved  faces  are  much  the  best.  Diamond  dust 
is  used  to  charge  metal  plates  of  various  kinds  for  jewellers, 
lapidaries,  and  others.  Drills  are  made  of  small  splinters 
of  bort,  and  used  for  drilling  other  gems,  and  also  for 
piercing  holes  in  artificial  teeth  and  vitreous  substances 
generally;  and  others  of  iron  set  with  a  few  diamonds,  for 
drilling  rocks. 

Graphite. — Plumbago. 

Hexagonal.  Sometimes  in  six-sided  prisms  or  tables  with 
a  transversely  foliated  structure.  Usually  foliated,  and 
massive;  also  granular  and  compact. 

Lustre  metallic,  and  color  iron-black  to  dark  steel-gray. 
Thin  laminee  flexible.  H.  =  1-2.  G.  =  2-25-2-27.  Soils 
paper,  and  feels  greasy. 

Composition.  Commonly  95  to  99  per  cent,  of  carbon. 
B.B.  infusible,  both  alone  and  with  reagents;  not  acted 
upon  by  acids. 

Diff.  Resembles  molybdenite,  but  differs  in  being  unaf- 
fected by  the  blowpipe  and  acids.  The  same  characters 


120  DESCRIPTIONS   OF   MINERALS. 

distinguish  the  granular  varieties  from  any  metallic  ores 
they  resemble. 

Obs.  Graphite  (called  also  black  lead)  is  found  in  crys- 
talline rocks,  in  veins,  and  as  a  constituent  of  mica  schist 
or  gneiss;  also  in  crystalline  limestone;  in  argillyte,  and 
occasionally  in  sandstone.  In  Rhode  Island  and  at  Worces- 
ter, Mass.,  ft  occurs  in  beds  of  the  coal  formation.  Its 
principal  English  locality  at  Borrowdale,  in  Cumberland, 
is  now  nearly  exhausted. 

In  the  U,  States  it  is  worked  at  Roger's  Rock,  near  Ti- 
conderoga;  less  abundant  in  gneiss  at  Sturbridge,  Mass.; 
North  Brookfield,  Brimfield,  and  Hinsdale,  Mass.;  Corn- 
wall and  Ashford,  Ct.;  Brandon,  Vt.;  Rossie,  in  St.  Law- 
rence Co.;  near  Amity,  Orange  Co.,  N.  Y.;  Greenville, 
N.  C.;  near  Attleboro,  in  Bucks  County,  Pa.;  Wake, 
N.  C. ;  on  Tyger  River,  and  at  Spartanburg,  near  the  Cow- 
pens  Furnace,  and  Greenville,  S.  C.;  Albany  Co.,  Wyom- 
ing; Pitkin,  Gunnison^Co.,  Col.;  Black  Hills,  Dak.;  Sonora 
Mine,  Tuolumne  Co.,  Cal. ;  N.  Mexico;  also  of  excellent 
quality  in  Canada,  in  Buckingham,  Fitzroy,  and  Grenville, 
but  not  worked  in  1884. 

Ceylon,  Bavaria,  and  Siberia  afford  most  of  the  foreign 
graphite.  About  17,348,000  pounds  were  imported  into 
the  U.  States  in  1883.  In  the  same  year  the  yield  of  the 
U.  States  was  only  575,000  pounds,  and  all  was  from  the 
Ticonderoga  mine;  in  1884  this  mine  was  not  worked. 

For  the  manufacture  of  the  best  pencils  the  granular 
graphite  was  thought  necessary,  and  hence  the  former  great 
value  of  the  Borrowdale  mine,  where  the  texture  was  pecu- 
liarly fine  and  firm.  But  now  the  graphite  is  ground  up, 
and  then  compressed  under  heavy  pressure,  and  thus  the 
fine  texture  and  firmness  required  may  be  obtained  with 
any  pure  graphite,  though  some  cement  is  generally  used; 
fine  clay  is  added  to  make  the  harder  pencils. 

Graphite  is  extensively  employed  for  diminishing  the 
friction  of  machinery;  also  for  the  manufacture  of  crucibles 
and  furnaces;  in  electrotyping;  as  a  polish  for  iron  stoves 
and  railings.  For  crucibles  it  is  mixed  with  half  its  weight 
of  clay.  Price,  1-10  dollars  per  cwt.,  according  to  quality. 

Carbonic  Acid. 

Carbonic  acid — carbon  dioxide  of  chemistry — is  the  gas 
that  gives  briskness  to  the  Saratoga  and  many  other  mineral 


MINERALS   CONSISTING    OF   THE   ACIDIC    ELEMENTS.    121 

waters,  and  to  artificial  "soda  water."  Its  taste  is  slightly 
pungent.  It  extinguishes  combustion  and  destroys  life. 

Composition.  C02  =  Oxygen  72  '35,  carbon  37*65  =  100. 

This  gas  is  contained  in  the  atmosphere,  constituting 
about  3  parts,  by  volume,  in  10,000  parts;  and  it  is  present 
in  minute  quantities  in  the  waters  of  the  ocean  and  land. 
It  is  given  out  by  animals  in  respiration,  and  is  one  of  the 
results  of  animal  and  vegetable  decomposition;  and  from 
this  source  the  waters  derive  much  of  their  carbonic  acid. 
This  gas  is  the  cliolce-damp  of  mines,  where  it  is  often  the 
occasion  of  the  destruction  of  life.  It  is  often  present  also 
in  wells. 

Carbon  dioxide  (or  carbonic  acid)  is  given  out  by  lime- 
stone (or  calcium  carbonate)  when  it  is  heated;  and  quick- 
lime  is  limestone  from  which  C02has  been  expelled  byneat, 
a  process  carried  on  usually  in  a  limekiln.  It  is  expelled 
also  by  sulphuric  acid,  with  the  formation  of  gypsum  (a 
hydrous  calcium  sulphate),  or  anhydrite  (an  anhydrous  cal- 
cium sulphate),  and  this  is  one  source  of  gypsum  beds  in 
rocks  of  different  ages.  These  processes  are  often  carried 
on  in  volcanoes,  and  hence  carbonic-acid  gas  is  common  in 
some  volcanic  regions.  The  Grotto  del  Cane  (Dog  Cave) 
at  the  Solfatara  near  Naples  is  a  small  cavern  filled  to  the 
level  of  the  entrance  with  this  gas.  It-  is  a  common  amuse- 
ment for  the  traveller  to  witness  its  effect  upon  a  dog  kept 
for  that  purpose.  He  is  held  in  the  gas  awhile  and  is  then 
thrown  out  apparently  lifeless;  in  a  few  minutes  he  recovers 
himself,  picks  up  his  reward,  a  bit  of  meat,  and  runs  off  as 
lively  as  ever.  If  continued  in  the  carbonic-acid  gas  a 
short  time  longer,  life  would  have  been  extinct. 

Carbonic  acid,  under  high_jressure,  becomes  a  liquid, 
and,  with  pressure  and  coldTawhrfe  snowlike  solid.  In 
the  liquid  state  it  is  often  found  in  microscopic  globules  in 
the  interior  of  crystallized  quartz, 'topaz,  and  some  other 
minerals;  and  when  this  is  true,  calcite  (calcium  carbonate) 
is  often  present  in  the  same  or  an  adjoining  rock. 

Besides  the  calcium  carbonate  in  nature,  there  are  also  carbonates 
of  ammonium,  sodium,  barium,  strontium,  magnesium,  iron,  manga- 
nese, zinc,  copper,  lead,  nickel,  cobalt,  bismuth.,  uranium,  cerium, 
and  lanthanum. 


122 


DESCRIPTIONS   OF   MINERALS. 


II.  MINERALS  CONSISTING  OF  THE  BASIC  ELE- 
MENTS WITH  OR  WITHOUT  ACIDIC— THE 
SILICATES  EXCLUDED. 

I.  GOLD. 

Gold  occurs  mostly  native,  being  either  pure,  or  alloyed 
with  silver  and  other  metals.  It  is  occasionally  found  min- 
eralized by  tellurium,  making  part  of  the  valuable  minerals 
Sylvanite,  Nagyagite,  and  Petzite. 

Native  Gold. 

Isometric.  In  octahedrons,  dodecahedrons;  without 
cleavage.  Also  in  arborescent  forms,  consisting  of  strings 
of  crystals,  filiform,  reticulated;  also  in  grains,  thin  laminae 
or  scales,  and  in  masses. 

Color  various  shades  of  gold-yellow,  paler  when  alloyed 
with  silver,  and  occasionally  nearly  silver-white.  Emi- 
nently ductile  and  malleable.  H.  =  2-5-3.  G.  when  pure 
(native)  19-19-30,  varying  to  15  and  12  according  to  the 
metals  alloyed  with  the  gold.  Fuses  at  2016°  F.  (1102° 
C.). 

Composition.  Native  gold  is  usually  alloyed  with  silver. 
The  finest  native  gold  from  Russia  yielded  gold  98*96, 


silver  0-16,  copper  0-35,  iron  0-05;  G.  =  19-099.  A  gold 
from  Marmato  afforded  only  73*45  per  cent,  of  gold,  with 
26-48  per  cent,  of  silver;  G.  =  12-666.  This  last  is  in  the 
proportion  of  3  of  gold  to  2  of  silver.  The  following  pro- 
portions also  have  been  observed:  3-J-  to  2;  5  to  2;  3  to  1; 


MINERALS   CONSISTING    OF   THE   BASIC    ELEMENTS.       123 

4  to  1,  and  this  the  most  common;  6  to  1  is  also  of  frequent 
occurrence.  Average  of  California  native  gold  is  88  per 
cent,  gold,  and  the  range  mostly  between  87  and  89;  the 
range  of  the  Canadian,  mostly  between  85  and  90;  of  Aus- 
tralian, between  90  and  96  per  cent.,  and  the  average  93|. 
The  Chilian  gold  aiforded  Domeyko  84  to  96  per  cent,  of 
gold,  and  15  to  3  per  cent,  of  silver.  The  more  argentif- 
erous gold  has  been  called  Elcctrum;  the  atomic  proportion 
of  1  :  1  between  the  gold  and  silver  corresponds  to  35 '5 
per  cent,  of  silver,  and  that  of  2  :  1,  to  21  '6  per  cent. 

Copper  is  occasionally  found  in  alloy  with  gold,  and  some- 
times also  iron,  bismuth,  palladium,  and  rhodium.  A 
rhodium-gold  from  Mexico  gave  the  specific  gravity  15 '5— 
16*8,  and  contained  34  to  43  per  cent,  of  rhodium.  A  bis- 
muth gold  has  been  called  Maldonite. 

Diff.  Iron  and  copper  pyrites  are  often  mistaken  for  gold 
by  those  inexperienced  in  ores;  but  these  are  brittle  min- 
erals, while  gold  may  be  cut  in  slices,  and  flattens  under  a 
hammer.  Pyrite  is  too  hard  to  yield  at  all  to  a  knife,  and 
copper  pyrites  (chalcopyrite)  affords  a  dull  greenish  pow- 
der. Moreover  pyrite  gives  off  sulphur  when  strongly 
heated,  while  gold  melts  without  odor. 

Obs.  Mostly  confined  to  veins  of  quartz,  intersecting  or 
interlaminated  with  subcrystalline  slaty  or  schistose  rocks, 
especially  hydromica  and  chloritic  schists;  occurs  spar- 
ingly in  similar  or  other  veins  in  granite,  gneiss,  or  mica 
schist;  sometimes  occurs  in  slate  rocks  adjoining  the  veins. 
Found  in  traces,  according  to  J.  J.  Stevenson,  in  the  tra- 
chytes of  Colorado,  and  in  Silurian  and  Carboniferous 
quartzites.  Gold  also  exists  in  sea-water — -nearly  1  grain 
to  a  ton  of  water. 

The  quartz  is  frequently  cellular  for  a  considerable  dis- 
tance from  the  surface  owing  to  the  alteration  and  removal 
of  pyrite,  galena,  or  other  metallic  ores  that  may  be  accom- 
paniments of  the  gold,  and  the  cavities  are  usually  rusty 
with  oxide  of  iron,  and  sometimes  contain  particles  of  sul- 
phur left  by  the  decomposing  pyrite,  and  also  strings  or 
laminae  of  gold  derived  from  the  decomposed  minerals, 
The  rock  in  this  cavernous  state  is  rather  easily  quarried 
out;  but  deep  below,  where  the  minerals  are  not  removed 
by  decomposition,  mining  is  far  more  difficult.  The  aurif- 
erous quartz  often  contains  no  gold  that  the  naked  eye  or 
even  a  pocket  lens  can  detect.  The  pyrite  of  a  gold  region 


1.24  DESCRIPTIONS   OF   MINERALS. 

is  often  so  auriferous  as  to  make  a  very  valuable  gold  ore, 
and  this  is  true  also  of  galenite. 

While  quartz  veins  are  to  a  large  extent  the  original  re- 
positories of  native  gold,,  a  large  part  of  the  gold  of  aurif- 
erous regions  comes  from  the  sand  and  gravel  beds,  in 
which  it  occurs  in  flattened  grains,  and  sometimes  in  lumps 
or  nuggets.  By  different  methods — erosion  by  running 
waters,  movements  of  glaciers,  natural  decomposition,  and 
other  disintegrating  action — the  gold-bearing  rocks  have 
been  extensively  reduced  to  earth  and  stones,  and  this  loose 
material  has  been  distributed  along  the  river-courses,  mak- 
ing vast  alluvial  or  diluvial  gravelly  formations.  From 
these  gravels  the  gold  is  obtained  by  simple  washing,  thus 
taking  advantage  of  the  high  specific  gravity  of  gold. 
Streams  are  carried  in  aqueducts  and  thrown  in  great  jets 
against  the  gravel  bluffs  to  reduce  the  material  to  loose 
earth  and  prepare  it  for  further  washing  by  the  same  water 
in  sluices  arranged  for  the  purpose. 

The  minerals  most  common  in  gold  regions  are  platinum, 
iridosmine,  magnetite,  pyrite,  galenite,  ilmenite,  chalco- 
pyrite,  blende,  arsenopyrite,  tetradymite,  zircon,  rutile, 
barite;  also  in  some  cases  wolfram,  scheelite,  brookite,  mo- 
nazite,  and  diamond.  Platinum  and  iridosmine  accompany 
the  gold  of  the  Urals,  Brazil,  and  California;  and  diamonds 
are  found  in  the  gold  region  of  Brazil,  and  occasionally  in 
the  Urals,  United  States,  and  Australia.  Auriferous  pyrite 
is  worked  for  its  gold  in  Colorado,  and  arsenopyrite  at 
Deloro  in  Canada. 

Gold  is  widely  distributed  over  the  globe.  In  AMERICA, 
it  occurs  in  Brazil  (where  formerly  a  greater  part  of  that 
used  was  obtained)  along  the  chain  of  mountains  which 
runs  nearly  parallel  with  the  coast,  especially  near  Villa 
Rica,  and  in  the  province  of  Minas  Geraes;  in  New  Granada, 
at  Antioquia,  Choco,  and  Giron;  in  Chili;  sparingly  in  Peru 
and  Mexico;  in  Arizona;  in  the  Coast  Range,  and,  much 
more  abundantly,  in  the  Sierra  Nevada,  Cal. ;  in  Oregon, 
British  Columbia,  and  Alaska;  in  New  Mexico,  Colorado, 
and  Wyoming,  the  Black  Hills  in  Dakota,  and  other  parts 
of  the  Rocky  Mountain  region;  in  the  Appalachians  from 
Virginia  to  Georgia,  a  region  that  formerly  produced  annu- 
ally nearly  a  million  of  dollars;  sparingly  in  Vermont,  New 
Hampshire,  and  other  New  England  States;  in  Nova  Scotia 
along  its  southern  shore,  chiefly  to  the  eastward  of  Halifax; 


GOLD.  125 

in  Beauce  County,  Canada;  also,  north  of  Lake  Superior; 
and  in  the  gravel  of  Illinois  and  Indiana. 

In  EUROPE,  it  occurs  sparingly  in  Cornwall  and  Devon, 
England;  North  Wales,  Scotland,  and  Ireland,  formerly  in 
the  County  of  Wicklow,  where  a  nugget  of  22  ounces  was 
found;  and  in  France,  very  sparingly  in  the  Department  of 
Isere;  in  the  sands  of  the  Rhine,  the  Reuss,  and  the  Aar; 
in  Tyrol  and  Salzburg;  on  the  southern  slope  of  the  Pen- 
nine Alps,  from  the  Simplon  and  Monte  Rosa  to  the  Valley 
of  Aosta,  Northern  Piedmont,  where  nearly  6000  ounces 
were  obtained  in  1867;  more  abundantly  in  Hungary,  at 
Konigsberg,  Schemnitz,  and  Felsobanya,  and  in  Transyl- 
vania, at  Kapnik,  Vdrospatak,  and  Offenbanya;  in  Spain, 
formerly  worked  in  Asturias;  in  Sweden,  at  Edelfors. 

In  the  Urals  are  valuable  mines  at  Beresof,  and  other 
places  on  the  eastern  or  Asiatic  flank  of  this  range,  and  the 
comparatively. level  portions  of  Siberia;  also  in  the  Altai 
Mountains.  Also  in  the  Cailas  Mountains  in  Little  Thibet; 
sparingly  in  the  rivers  of  Syria  and  other  parts  of  Asia 
Minor;  in  Ceylon,  China,  Japan,  Formosa,  Java,  Sumatra, 
Western  Borneo,  the  Philippines,  and  New  Guinea. 

In  AFRICA,  at  Kordofan,  between  Darfour  and  Abyssinia; 
also  south  of  Sahara,  in  the  western  part  of  Africa,  from 
the  Senegal  to  Cape  Palmas  ;  also  along  the  coast  opposite 
Madagascar,  between  the  22d  and  35th  degrees  south  lati- 
tude, in  the  Transvaal  Republic.  Other  regions  are  Tas- 
mania, New  Zealand,  and  New  Caledonia. 

General  Remarks. — The  most  productive  gold  regions  at  the  present 
time  are  those  of  Australia  and  California. 

In  Australia  the  richest  mines  are  those  of  Victoria  and  New  South 
Wales.  Victoria  yielded,  in  1856,  3,000,000  ounces,  and  in  1875, 
1,195,250;  New  South  Wales,  in  1875,  227,000  ounces;  and  all  Aus- 
tralia in  1884,  $29,000,000.  The  Australian  gold  was  first  made 
known  to  the  world  in  1851.  The  localities  discovered  were  on 
Summer  Hill  Creek  and  the  Lewis  Pond  River  (near  lat.  33°  N., 
long.  149°-150°  E.),  streams  which  run  from  the  northern  flank  of 
the  Coriobolas  down  to  the  river  Macquarie,  a  river  flowing  westward 
and  northward;  it  wavS  soon  afterward  found  on  the  Turon  River, 
which  rises  in  the  Blue  Mountains;  and  finally  a  region  of  country 
1000  miles  in  length,  north  and  south,  was  proved  to  be  auriferous; 
the  country  is  a  region  of  mctamorphic  rocks,  granite  and  slates,  and 
in  many  parts  abounds  in  quartz  veins.  Queensland  and  South 
Australia,  and  also  Tasmania  arid  New  Zealand,  afford  gold. 

Gold  was  first  discovered  in  California  in  the  spring  of  1848,  in 
placer  deposits  on  the  American  Fork,  a  tributary  to  the  Sacramento, 


126 


DESCRIPTIONS   OF   MINERALS. 


near  the  mouth  of  which  Sutler's  establishment  was  situated.  Soon 
the  gravels  along  Feather  River,  another  affluent,  18  or  20  miles 
north,  were  proved  to  abound  in  gold  about  its  upper  portions;  and  it 
was  not  long  after  before  each  stream  in  succession,  north  and  south, 
along  the  western  slope  of  the  Sierra  Nevada  was  found  to  flow  over 
auriferous  sands.  The  gold  region  as  now  developed  extends  along 
that  chain,  through  the  whole  length  of  the  great  north  and  south 
valley  which  holds  the  rivers  and  plains  of  the  Sacramento  and  San 
Joaquin.  It  continues  south  nearly  to  the  Tejon  pass,  in  latitude 
35°,  and  north  beyond  the  Shasta  Mountains  to  the  Umpqua,  and 
less  productively  into  Oregon  and  Washington,  and  in  British  Co- 
lumbia and  Alaska.  Gold  also  occurs  in  some  places  in  the  Coast  range 
of  mountains.  Even  the  site  of  San  Francisco  has  been  found  to 
contain  traces.  North  of  Shasta  Mountain  there  are  mines  on  the 
Klamath  and  the  Umpqua,  and  on  the  sea-shore  between  Gold  Bluff, 
in  41°  30'  south  of  the  Klamath  (30  miles  south  of  Crescent  City)  to 
the  Umpqua. 

The  yield  of  gold  in  the  United  States  up  to  1848,  before  the  open- 
ing of  the  California  mines,  was  $13,250,000;  during  the  year  1848  to 
1879  inclusive,  $1,484,000,000;  years  1880  to  1884  inclusive  $163,000,- 
000;  making  a  total  of  $1,647,013,250. 

In  California,  the  yield  of  gold  for  1848  was  about  $45,000  ;  for 
1849,  over  6,000,000;  for  1850,  over  36,000,000;  and  for  1851  to  1857 
inclusive,  an  average  of  $55,000,000;  after  which  there  was  a  gradual 
decline  from  the  exhausting  of  the  placer  deposits ;  in  1863,  it  was 
$30,000,000;  in  1870,  $28,500,000;  in  1872,  $20,000,000;  in  1884, 
$13,600,000. 

In  Colorado,  gold  mines  occur  in  Gilpin  County,  among  Archaean 
rocks,  and  much  less  productively  in  Clear  Creek,  Park,  Boulder, 
Lake,  Summit,  Rio  Grande,  San  Miguel,  and  La  Plata  counties. 
The  yield  in  1874  amounted  to  $2,102,487,  of  which  $1,525,447  were 
from  Gilpin  County;  in  1884,  $4,250,000. 

Nevada,  where  gold  was  first  discovered  in  1850,  produced  from 
the  Comstock  lode  (see  p.  123),  in  1858,  1859,  its  first  years,  $257,000; 
in  1875,  about  $11,740,000,  and  the  rest  of  Nevada,  $2,256,000,  mak- 
ing in  all  nearly  $14,000,000;  and  in  1876,  the  Comstock  lode  yielded 
$18,000,000,  and  the  rest  of  Nerada  about  $1,338,000;  but  all  Nevada, 
in  1884,  only  $3,500,000. 

For  the  several  States  and  Territories  in  1884,  the  yield  of  gold  was 
as  follows : 


California $13.600,000 

Colorado 4,250,000 

Nevada 3,500.000 

Dakota 3.300.000 

Montana 2,170,000 

Idaho  1,250.000 

Arizona 930,000 

Oregon  660,000 

New  Mexico 300,000 


Alaska $200.000 

Nortli  Carolina 1 57, 000 

Georgia 137,000 

Utah 120,000 

Washington 85,000 

South  Carolina 57,000 

Wyoming 6,000 

Virginia 2,000 

Alabama,  Tenn.,  etc  . .  76,000 


GOLD. 


137 


The  yield  of  the  United  States  in  gold  and  silver  from  1870  to  1884 
was  as  follows: 


Gold. 

Silver. 

Total. 

1870 

$33  750  000 

$17  320  000 

$51,070  000 

1871  

34  398  000 

19  286  000 

53  684  000 

187:3  

38,177.395 

19  924,429 

58,101,824 

1873  .... 

39  206  558 

27  483  802 

66  689  860 

1874  

38  466  488 

29  699,122 

68,165  610 

1875 

39  968  194 

31  635  239 

71  603  433 

1876  

42  886  935 

39  292  924 

82  179  859 

1877  

1878 

44,880.223 
37  576  030 

45.846,109 
87  248  137 

90,726.332 
74  824  167 

1879  

31  420  262 

37  032  857 

68  453  119 

1880  
1881 

32,559.067 
30  653  959 

38,033,055 
42  987  613 

70,592,122 
73  641  572 

1882  

29  Oil  318 

48  133  039 

77  144  357 

1883  

30  000,000 

46  200  000 

76,200  000 

1884 

30  800  000 

48  800  000 

79  600  000 

The  yield  of  Nova  Scotia  in  1884  was  16,079  ounces,  and  in  1885 
22,203  ounces.  The  Central  and  South  American  States  yielded  of 
gold  in  1882,  Mexico,  936,223;  Venezuela,  2,595,077;  Colombia, 
3,856,000;  Brazil,  741,694;  Peru,  119,250;  Chili,  163,000;  Argentine 
Republic.  78,546;  Bolivia,  72,375;  making  a  total  of  a  little  more  than 
8,560,000  dollars.  The  yield  of  gold  from  all  America  from  1492  to 
the  year  1800,  was  about  $1,872,300,000. 

From  1800  to  1847  inclusive,  48  years,  the  yield  from  America, 
Europe,  and  Africa  is  stated  at  $429,200,000;  and  from  1848  to  1876 
inclusive,  29  years,  $3,381,500,000.  The  largest  annual  amount  was 
produced  in  the  year  1856,  in  which  the  yield  was  $147,600,000;  and 
next  to  this,  in  1859,  with  $144,900,000;  as  shown  in  the  annexed 
table,  giving  the  amounts  in  millions  of  dollars: 


1848 67-5 

1849 87-0 

1850 93-2 

1851 120-0 

1852 193-7 

1S53 155-0 

1854 127-0 

1855 135-0 

1856  147-6 

1857..  ..133-3 


1858 144-6 

1859 144-9 

1860 119-3 

1861 113-8 

1862 107-8 

1863 107-0 

1864 113-0 

1865... 130-7 

1866 122-2 

1867..  ..114-0 


1868 109-7 

1869 106-2 

1870 106-9 

1871 107-0 


1872. 
1873. 
1874. 
1875. 
1876. 
1884. 


99-6 
97-2 
90-8 
97-5 
90-0 
41-3 


128 


DESCRIPTIONS   OF   MINERALS. 


The  following  table  gives  totals  for  the  years  stated  : 


Russia. 

United 
States. 

Mexico 
and  South 
America. 

Australia. 

Other 
Countries. 

Total. 

1850 

$16  950000 

$27  500,000 

1855.. 
I860.. 
1865.. 
1870.. 

1875.. 
1884.. 

14,200,000 
15,265.000 
16,135,000 
22,070,000 
20,000,000 
22,000,000 

73,700,000 
46,000,000 
53,225,000 
33,750,000 
40,000,000 
30,800.000 

$5.000.000 
4,500,000 
4,000,000 
2,500,000 
3,750,000 
9,400,000 

$60,325,000 
53,500,000 
44,100,000 
29,150,01)0 
28.750.000 
28,500,000 

$2,500.000 
2,500,000 
2,500,000 
2,500,000 
2,500,000 
4,300,000 

$155.725,000 
120,765,000 
119.960.000 
89,970,000 
95,000,000 
95,000,000 

Masses  of  gold  of  considerable  size  have  been  found  in  North  Caro- 
lina. The  largest  was  discovered  in  Cabarrus  County;  it  weighed  28 
pounds  avoirdupois  ("steel -yard  weight,"  equals  37  pounds  troy),-and 
was  8  or  9  inches  long,  by  4  or  5  broad,  and  about  an  inch  thick.  In 
Paraguay  pieces  from  1  to  50  pounds  weight  were  taken  from  a  mass 
of  rock  which  fell  from  one  of  the  highest  mountains. 

The  largest  masses  of  gold  yet  discovered  have  been  found  in  aurifer- 
ous gravel.  The  "Blanch  Barkley  Nugget,"  found  in  South  Austra- 
lia, weighed  146  pounds,  and  only  six  ounces  of  it  were  gangue  ;  and 
one  still  larger,  the  "  Welcome  Nugget,"  from  Victoria,  weighed 
2195  ounces,  or  nearly  183  pounds,  and  yielded  £8376  10s.  Qd.  sterling 
of  gold.  Two  others  from  Victoria  weighed  1621  and  1105  ounces. 
In  Russia,  a  mass  was  found  in  184.2,  near  Miask,  weighing  96  pounds 
troy  ;  another  of  27  pounds  and  several  of  16  pounds  have  been  found 
in  the  Urals.  The  largest  mass  reported  from  California  weighed  160 
pounds.  A  remarkably  beautiful  mass,  consisting  of  a  congeries  of 
crystals,  weighing  201  ounces  (value  $4000),  was  found  in  1865,  seven 
miles  from  Georgetown,  in  El  Dorado  County. 

The  origin  of  gold  veins,  or  rather  of  the  gold  in  the  veins,  is  little 
understood.  The  rooks,  as  has  been  stated,  are  metamorphic  slates 
that  have  been  crystallized  by  heat ;  and  they  are  the  hydromica,  chlo- 
ritic,  and  argillaceous,  that  have  been  but  imperfectly  crystallized, 
rather  than  the  mica  schist  and  gneiss,  which  are  well  crystallized  ;  and 
the  veins  of  quartz  which  contain  the  gold  occupy  fissures  through 
the  slates  and  openings  among  the  layers,  which  must  have  been  made 
when  the  metamorphic  changes  or  crystallization  took  place.  It  was 
a  period,  for  each  gold  region,  of  long-continued  heat  (occupying, 
probably,  a  prolonged  age),  and  also  of  vast  uplif  tings  and  disturbances 
of  the  beds  ;  for  the  beds  are  tilted  at  various  angles,  and  the  veins 
show  where  were  the  fractures  of  the  layers,  or  the  separations  and 
gapings  of  the  tortured  strata.  The  heat  appears  not  to  have  been  of 
the  intensity  required  for  the  better  crystallization  of  the  more  per- 
fectly crystalline  schists.  The  quartz  veins  could  not  have  been  filled 
from  below,  by  injection  ;  they  must  have  been  filled  either  laterally, 
or  from  above.  In  all  such  conditions  of  upturning  and  metainorph- 
ism,  the  moisture  present  would  have  become  intensely  heated,  and 
hence  have  had  great  dissolving  and  decomposing  power  ;  it  would 
have  taken  up  silica  with  alkalies  from  the  rocks  (as  happens  in  all 
Geyser  regions),  along  with  whatever  other  mineral  substances  were 
capable  of  solution  or  removal ;  and  the  vapor,  thus  laden,  would  have 


SILVER.  129 

filled  all  open  spaces,  there  to  make  depositions  of  the  silica  and  other 
ingredients  it  contained.  These  mineral  ingredients  would  have  been 
derived  either  from  the  rock  adjoining  the  veins  or  opened  spaces,  or 
from  depths  below  through  ascending  vapors.  By  one  or  both  of 
these  means  the  quartz  must  have  received  its  gold,  pyrite,  and  ores 
of  lead,  copper,  and  other  materials— all  having  been  carried  into 
the  open  cavities  at  the  same  time  with  the  silica  or  quartz.  The 
pyrite  of  the  vein,  by  being  auriferous,  shows  that  it  was  crystallized 
under  the  same  circumstances  that  attended  the  depositing  of  the 
gold  in  strings,  crystals,  and  grains  ;  and  the  same  is  often  true  of  the 
galena. 

Gold  coin  of  the  United  States  contains  90  parts  of  gold  to  10  of  an 
alloy  of  copper  and  silver,  and  an  eagle  weighs  258  grains.  An  ounce 
of  pure  gold  is  worth  about  $20.67. 

Calaverite.  A  bronze-yellow  gold  telluride  ;  G-.  =  9 '043  ;  Au  Te2  = 
Tellurium  55*5,  gold  44'5  =  100,  with  a  little  silver.  Occurs  mas- 
sive at  the  Stanislaus  Mine,  California,  and  the  Red  Cloud  Mine, 
Colorado,  and  also  the  Keystone  and  Mountain  Lion  mines,  in  the 
Magnolia  District. 

KrenneriU.  Another  gold  telluride,  silver- white  to  brass-yellow, 
from  Nagyag  in  Transylvania. 

Ejtfaamte,  called  also  Graphic  tellurium  (see  p.  132). 

Nagyagite.     Telluride  of  lead  containing  gold  (see  p.  149). 

Petzite.    Telluride  of  silver  and  gold,  allied  to  Hessite  (p.  132). 

II.  SILVER. 

Silver  occurs  native,  and  alloyed  with  gold ;  also  com- 
bined with  sulphur,  selenium,  tellurium,  arsenic,  antimony, 
bismuth,  chlorine,  bromine,  or  iodine ;  but  never  as  an  ox- 
ide, carbonate,  sulphate,  or  phosphate. 

Native  Silver. 

Isometric.  In  octahedrons  and  other  forms.  No  cleavage 
apparent.  Often  in  filiform  and  arborescent  shapes,  the 
threads  having  a  crystalline  character  ;  also  in  laminae,  and 
massive. 

Color  and  streak  silver-white  and  shining.  Often  black 
externally  from  tarnish.  Sectile.  Malleable.  H.  =  2  '5-3. 
G.  =  10-1-11-1  (for  pure  silver,  10-92). 

Composition.  Usually  an  alloy  of  silver  and  copper,  the 
latter  often  amounting  to  10  per  cent.  Also  alloyed  with 
gold,  as  mentioned  under  that  metal.  A  bismuth  silver 
from  Copiapo,  S.  A.,  contained  16  per  cent,  of  bismuth. 

B.  B.  fuses  easily  to  a  silver- white  globule.  Dissolves  in 
nitric  acid,  from  which  it  is  precipitated  as  white  chloride 
9 


130  DESCRIPTIONS   OF   MINERALS. 

on  adding  hydrochloric  acid.  A  clean  plate  of  copper  im- 
mersed in  the  nitric  solution  becomes  coated  with  silver. 
Sulphur  gases  blacken  or  tarnish  silver,  producing  a  sul- 
phide. 

Diff.  Distinguished  by  being  malleable  ;  from  bismuth 
and  other  white  native  metals  by  affording  no  fumes  before 
the  blowpipe  ;  by  affording  a  precipitate  with  hydrochloric 
acid  (the  chloride  of  silver,  which  becomes  black  on  ex- 
posure. 

Obs.  Occurs  in  masses  and  string-like  arborescences, 
penetrating  the  gangue,  or  its  minerals,  in  various  silver 
mines.  It  is  also  found  mixed  with  native  copper.  Sea- 
water  contains  1  part  in  100  million ;  and  it  has  been  cal- 
culated that  the  whole  amount  in  the  ocean  is  not  less  than 
2,000,000  tons. 

The  mines  of  Norway,  at  Kongsberg,  formerly  afforded 
magnificent  specimens  of  native  silver,  but  they  are  now 
mostly  under  water.  One  mass  from  this  locality,  at  Co- 
penhagen, weighs  500  pounds  ;  and  two  other  masses  have 
been  found  of  238  and  436  pounds.  Other  European  locali- 
ties are  in  Saxony,  Bohemia,  the  Hartz,  Hungary,  Dauph- 
iny.  Peru  and  Mexico  also  afford  native  silver.  A  Mexican 
specimen  from  Batopilas,  weighed  when  obtained  400  pounds; 
and  one  from  Southern  Peru  (mines  of  Huantajaya)  weighed 
over  8  cwt.  Arizona  is  reported  to  have  produced  one  mass 
weighing  2700  pounds.  In  the  United  States,  in  the  Lake 
Superior  region,  the  silver  generally  penetrates  the  copper 
in  masses  and  strings,  and  is  very  nearly  pu,re,  notwith- 
standing the  copper  about  it.  Large  masses  occur  at  the 
Idaho  Silver  Mine,  called  the  Poor  Man's  Lode ;  and  in 
strings  it  is  occasionally  found  in  the  mines  of  Nevada, 
California,  and  Colorado.  Native  silver  has  also  been  ob- 
served at  the  Bridge  water  copper  mines,  N,  J.  ;  and  in 
handsome  specimens  at  King's  Mine,  Davidson  Co.,  N.  C.; 
Newburyport,  Mass. 

Native  Amalgam.  Silver-white  ;  consists  of  silver  and  mercury  ;  the 
compounds  Ag  Hg  =  Silver  351,  mercury  64'9,  and  Ag2Hg3  =  Silver 
26-5,  mercury  73 '5,  are  included. 

Arguerite.  A  kind  from  Chili  ;  contains  86*6  per  cent,  of  silver 
(AgJ2Hg);  from  Arqueros  ;  Vitalle  Creek,  British  Columbia.  Another, 
Agi  8Hg,  is  Kongsbergite,  from  Kongsberg,  Sweden  ;  Arqueros,  Chili. 
Another  has  been  called  Bordosite. 


SILVER.  131 


SULPHIDES,   SELENIDES,   TELLUKIDES,   ANTIMONIDES. 
Argentite.— Silver  Glance.     Sulphuret  of  Silver. 

Isometric.  In  dodecahedrons  more  or  less  modified. 
Cleavage  sometimes  apparent  parallel  to  the  faces  of  the 
dodecahedron.  Also  reticulated  and  massive. 

Lustre  metallic.  Color  and  streak  blackish  lead-gray  ; 
streak  shining.  Verysectile.  H.  =  2-2 '5.  G.  =  7  '19-7  '4. 

Composition.  When  pure,  Ag2  S  =  Sulphur  12*9,  silver 
87*1.  B.B.  on  charcoal  in  O.F.  intumesces,  gives  off  the 
odor  of  sulphur,  and  finally  affords  a  globule  of  silver. 

Diff.  Kesembles  some  ores  of  copper  and  lead,  and  other 
ores  of  silver,  but  is  distinguished  by  being  easily  cut,  like 
lead,  with  a  knife  ;  and  also  by  affording  a  globule  of  silver 
on  charcoal  by  heat  alone.  Its  specific  gravity  is  much 
higher  than  that  of  any  copper  ores. 

Obs.  This  important  ore  of  silver  occurs  in  Europe  prin- 
cipally at  Annaberg,  Joachimsthal,  and  other  mines  of  the 
Erzgebirge;  at  Schemnitz  and  Kremnitz,  in  Hungary,  and 
at  Freiberg  in  Saxony.  It  is  a  common  ore  at  the  Mexican 
silver  mines,  and  also  in  the  mines  in  South  America.  It 
occurs  in  Arizona,  with  chalcocite,  at  the  Heintzelman 
Mine;  in  Nevada;  in  Colorado,  Clear  Creek  Co.,  near 
Georgetown.  A  mass  of  "sulphuret  of  silver"  is  stated 
by  Troost  to  have  been  found  in  Sparta,  Tennessee. 

Acanthite.  An  ortho rhombic  silver  sulphide,  Ag2S,  from  Joachim- 
stahl.  Daleminzite.  Another,  from  near  Freiberg. 

Stromeijerite.  Steel-ejray  silver-copper  sulphide,  Ag2S  -f-  Cu2S  = 
Sulphur  15-7,  silver  53  1,  copper  31 '2  =  100 ;  H  =  2'5-3  ;  G.  =  G'2G  ; 
B.B.  fuses  and  gwcs  in  the  open  tube  an  odor  of  sulphur,  but  yields 
a  silver  globule  only  by  cupellation  with  lead.  Peru,  Silesia,  Chili, 
Siberia,  and  Arizona. 

Stcrnbergite.  .  Silver-iron  sulphide,  containing  30  to  35  per  cent, 
of  silver  ;  highly  foliated,  resembling  graphite,  and  like  it  leaving  a 
tracing  on  paper  ;  the  thin  lamina?  flexible  ;  color  pinchbeck  brown  ; 
streak  black  ;  G.  =  4'215.  Joachimsthal  and  Johanngcorgenstadt ; 
Arizona.  Argyropyrite  (G.  =  4'206)  from  Freiberg,  and  Frieseite 
from  Joachimsthal,  are  varieties  of  sternbergite.  Argentopyrite  con- 
tains 26  5  of  silver,  and  is  a  related  species,  from  Andreasberg. 

Naumannite.  Silver-lead  sclenide,  in  iron-black  cubes  and  mas- 
sive ;  G.  =  8  ;  contains  11-10  per  cent,  of  silver.  The  Hartz. 

Hessite.  Silver  telluride,  Ag2Te  =  Tellurium  37 '2,  silver  62 '8  = 
100.  Color  between  lead-gray  "and  steel-gray;  sectile;  G.  =8'3— 8'6; 
B.B.  in  the  open  tube,  faint  sublimate  of  tellurous  acid  ;  on  charcoal 
with  soda  a  silver  globule.  The  Altai ;  at  Nagyag  and  Retzbanya ; 


132  DESCRIPTIONS   OF  MINERALS. 

Coquimbo,  Chili;  Calaveras  Co.,  Cal. ;  Red  Cloud  Mine,  Col.; 
Kearsarge  Mine,  Dry  Canon,  Utah. 

Petzite,  A  hessite  with  the  silver  replaced  in  part  by  gold.  G.  = 
8'7-9'4.  Between  steel-gray  and  iron-black.  Variety  from  Golden 
Rule  Mine  afforded  Genth  Tellurium  32*68,  silver  41 '88,  gold  25'60  = 
100'14.  Occurs  at  the  same  localities  with  hessite. 

Tapalpite.     Tclluride  of  bismuth  and  silver  from  Mexico. 

Sylvanite  or  Graphic  Tellurium.  Gold-silver  telluride  (Ag,  Au) 
Te3  =  (if  Ag  :  Au  =  1  : 1)  Tellurium  55'8,  gold  28'5,  silver  15'7  =  100. 
Color  and  streak  steel-gray  to  silver  white,  and  sometimes  nearly 
brass  yellow  ;  H.  =  1*5-2  ;  G.  =  7'9-8'33  ;  called  graphic  because  of 
a  resemblance  in  the  arrangement  of  the  crystals  to  writing  characters. 
Transylvania;  Calaveras  Co.,  Cal.;  Red  Cloud,  Grand  View,  and 
Smuggler  Mines,  Col. 

Stutzite.  Crystals  hexagonal ;  silver  telluride  ;  Ag4Te  ?  Transyl- 
vania. 

Eucairite.  Silver  copper  selenide,  containing  42-45  per  cent,  of 
pi'ver ;  color  between  silver-white  and  lead-gray ;  easily  cut  by  the 
knife.  From  Sweden  and  Chili. 

Dyscrasite,  or  Antimonial  Silver.  Silver  antimonide  ;  contains  78 
to  85  parts  of  silver,  and  has  nearly  a  tin-white  color  ;  G.  =  9'4-9'8  ; 
B.B.  fumes  of  antimony  pass  off,  leaving  finally  a  globule  of  silver. 
Wolfach,  Wiltichen  ;  Andreasberg  ;  Allemont  in  Dauphiny  ;  Bolivia, 
k.  A. 

Huntilite.  A  silver  arsenide ;  dark  gray  to  black,  amorphous  ; 
G.  —  7*47.  Silver  Islet,  L.  Superior.  Mcfarlanite  is  impure  huntilite. 

Animikite.    A  silver  antimonide.    Silver  Islet,  L.  Superior. 


SULPHARSENATES.   SULPHANTIMONATES. 

Pyrargyrite. — Ruby  Silver.     Dark  Red  Silver  Ore. 

Rhombohedral.     Rf\R  =  108°  42' ;  R/\i-2  —  129°  39'. 
Cleavage  parallel  to  R  imperfect.    Also  massive.     Black  to 
dark  cochineal-red,  with  the  streak  cochi- 
neal-red and  lustre  splendent  metallic-ada- 
mantine.    H.  =  2-2-5.     GL  —  5-7-5-9. 

Composition.  Ag3S3Sb  (  =  3AgQS  -f 
Sb2S3)  =  Sulphur  17 -7,  antimony  22'5, 
silver  59-8  — 100. 

B.  B.  fuses  very  easily ;  on  charcoal  a 
white  deposit  of  antimony  oxide,  and  with  soda  a  globule  of 
silver.  In  an  open  tube,  sulphurous  fumes  that  redden  lit- 
mus paper. 

^  Diff.  Its  red  streak,  and  its  reactions  for  antimony  and 
silver,  are  distinctive. 

Obs.  Occurs  at  Andreasberg  ;  also  in  Saxony;  Hungary; 
Cornwall ;  Mexico ;  Chili ;  Nevada  at  Washoe ;  abundant 


SILVER.  133 

about  Austin,  Eeese  River ;  at  Poor  Man's  Lode,  and  else- 
where, in  Idaho  ;  Arizona. 

Proustite,  or  Light  Red  Silver  Ore,  is  a  related  ore  con- 
taining arsenic  in  place  of  much  or  all  of  the  antimony, 
and  having  a  light-red  color,  splendent  lustre  ;  G.  =  5  '4-5  '6. 
Composition,  Ag3 S3 As  =  Sulphur  19 '4,  arsenic  15*1,  silver 
65 -5  =  100.  B.B.  gives  a  garlic  odor.  Occurs  with 
pyrargyrite  at  the  above-mentioned  localities,  and  in  micro- 
scopic crystals  in  Cabarrus  Co.,  N.  0. 

Stephanite.— Brittle  Silver  Ore.    Black  Silver. 

Orthorhombic.  I/\I  =115°  39'.  No  perfect  cleavage. 
Often  in  compound  crystals.  Also  massive.  Streak  and 
color  iron-black.  H.  =  2-2-5.  G.  =  6-27. 

Composition.  AgBS4Sb  (  =  5Ag2S  +  Sb.2S3)  =  Sulphur 
16-2,  antimony  15 '3,  silver  68*5.  B.B.  an  odor  of  sulphur 
and  also  fumes  of  antimony,  yielding  a  dark  metallic  glob- 
ule from  which  silver  may  be  obtained  by  the  addition  of 
soda.  Soluble  in  dilute  nitric  acid ;  the  solution  indicates 
the  presence  of  silver  by  silvering  a  plate  of  copper. 

Obs.  Occurs  with  other  silver  ores  at  Freiberg,  Schnee- 
berg,  and  Johanngeorgenstadt,  in  Saxony ;  also  in  Bohe- 
mia, and  Hungary.  An  abundant  ore  in  Chili,  Peru, 
and  Mexico ;  also  in  Nevada,  at  the  Comstock  Lode, 
and  at  Ophir,  and  Mexican  mines,  in  the  Eeese  Eiver  and 
Humboldt,  and  other  regions;  in  Colorado,  in  Clear  Creek 
Co.  and  elsewhere  ;  in  Idaho ;  Arizona.  Sometimes  called 
black  silver. 

Polybasite.  Near  stephanite  in  color,  specific  gravity,  and  composi- 
tion, but  contains  some  arsenic  and  copper,  with  64  to  72*2  per  cent, 
of  silver ;  orthorhombic,  and  usually  in  tabular  hexagonal  prisms, 
without  distinct  cleavage ;  G.  =  6 '214.  Freiberg;  Przibfam  ;  Mexico; 
Chili;  the  Reese  mines  in  Nevada  ;  Idaho  ;  Arizona. 

Miargyrite.  Antimonial  silver  sulphide,  containing  but  36*5  per 
cent,  of  silver,  and  having  a  dark  cherry-red  streak,  though  iron-black 
in  color.  H.  =  2-2'5  ;  G.  =  5'2-5'4  ;  B.B.  on  charcoal  gives  off  fumes 
of  antimony  and  an  odor  of  sulphur ;  and  in  the  oxidating  flame,  a 
globule  is  left  which  finally  yields  a  button  of  pure  silver.  Saxony  ; 
Bohemia  ;  Spain  ;  Mexico  ;  Arizona. 

Brongniardite.  In  regular  octahedrons  and  massive  ;  color  grayish- 
black;  G.  =  5 '95  ;  contains  about  25  per  cent,  of  silver,  with  lead, 
antimony,  and  sulphur.  From  Mexico. 

Polyargyrite.  Isometric,  having  cubic  cleavage  ;  near  polybasite  m 
composition  =  12Ag2S  +  Sb2S3.  Wolfach  in  Baden. 

Freicdehenite.  A  monoclinic  antimonial  silver-lead  sulphide  ;  color 
light  steel-gray  ;  G.  =  6-6.4  ;  H.  =  2-2'5  ;  contains  22  to  24  per  cent. 


134  DESCRIPTION'S   OF   MINERALS. 

of  silver.     Saxony  ;  Transylvania ;  Spain  ;   Arizona.     Diaphorite  is 
the  same  in  composition,  but  is  orthorhpmbic. 
Pyrostilpnite.    Another  monoclinic  silver  ore;  in  delicate  crystals 

frouped  like  stilbite  ;  color  fire-red.    Contains  62'3  per  cent,  of  silver, 
'reiberg  ;  Andreasberg ;  Przibram. 

Schirmerite.  Lead- gray  to  iron  black ;.  contains  silver,  lead,  with 
much  bismuth  and  sulphur.  Red  Cloud  Mine,  Col.,  and  elsewhere. 

CHLOKIDES,  BROMIDES,  IODIDES. 
Cerargy rite.— Horn  Silver.     Silver  Chloride. 

Isometric.  In  cubes,  with  no  distinct  cleavage.  Also 
massive.,  and  rarely  columnar  ;  often  incrusting.  H.  =  2- 
1*5;  G.  =  5*3-5 '5.  Color  gray,  passing  into  green  and 
blue ;  looking  somewhat  like  horn  or  wax,  and  cutting 
like  it.  Lustre  resinous,  passing  into  adamantine.  Streak 
shining.  Translucent  to  nearly  opaque. 

Composition.  Ag  01  =  Chlorine  24 '7,  silver  75  *3.  Fuses  in 
the  flame  of  a  candle,  and  emits  acrid  fumes.  B.B.  affords 
silver  easily  on  charcoal.  A  plate  of  iron  rubbed  with  it  is 
silvered. 

Obs.  A  very  common  ore  and  extensively  worked  in  the 
mines  of  South  America  and  Mexico ;  also  abundant  in 
Nevada;  in  Idaho  at  Poor  Man's  Lode;  in  Arizona;  Utah; 
Colorado;  in  Saxony,  Siberia,  Norway,  the  Hartz,  and  Corn- 
wall. A  variety  containing  mercury  occurs  at  the  mine 
La  Julia,  Northern  Chili. 

Bromyrite  or  Bromic  Silver.  Silver  bromide,  Ag  Br  =  Bromine 
42-6,  silver  57'4  =  100;  H.  =  2-3;  G.  =  5'8-6.  With  the  preceding, 
in  Mexico  and  Chili. 

Embolite.  Silver  chlorobromicle,  resembling  cerargyrite;  H.  —  1- 
1'5;  G.  =  5'3-5'8;  color  asparagus  to  olive  green;  contains  51  p.  c.  of 
silver  chloride  to  49  of  bromide.  Common  in  Chili;  also  found  in 
Chihuahua,  Mexico. 

lodyriie.  Silver  iodide,  Ag  I  =  Iodine  54'0,  silver  46  0  =  100; 
bright  yellow;  lustre  not  metallic,  like  the  preceding;  G.  =  5'5-5'7. 
Spain;  Chili;  Mexico;  the  Cerro  Colorado  Mine,  Arizona.  lodobrom- 
ite  is  a  yellow  brorn-iodo-chloride  of  silver,  in  octahedrons;  from  near 
Nassau. 

Tocornalite.    A  silver-mercury  iodide.     Chili. 

General  Remarks. — The  chief  sources  of  the  silver  of  commerce  are 
(1)  Native  silver;  (2)  the  sulphide,  Argentite  (or  vitreous  silver);  four 
species  among  the  sulpharsenites  and  sulphantimonites,  viz.,  (3) 
Prouslite,  or  the  light-red  or  ruby  silver  ore,  and  (4)  Pyrarcjyrite,  or 
dark  red  silver  ore;  (5)  Freieslebenite;  (6)  Argentiferous  tetrahedrite, 
which  contains  sometimes  10  to  30  per  cent,  of  silver;  (7)  Steplianite  or 


SILVER.  135 

brittle  silver  ore;  (8)  the  chloride,  called  horn-silver  or  Cerargyrite; 

(9)  the  bromide  and  chlorobromide,  Bromyrite  and  Embolite,  common 
in  Chili  and  Mexico,  especially  the  latter,  along  with  the  rarer  iodide; 

(10)  Argentiferous  Galenite,  often  called  silver-lead  ore.     Of  the  other 
ores  of  silver  mentioned  beyond,  the  most  important  are  Arquerite, 
common  especially  in  Chili,  and  Polybasite. 

Silver  ores  occur  in  rocks  of  all  ages  and  kinds,  from  gneiss, 
granite,  and  mica  schist,  to  sandstones,  shales,  and  limestones,  and 
from  Archaean  to  Tertiary.  Among  the  above-mentioned  ores, 
argentiferous  galenite,  or  silver-lead  ore.  is  of  very  prominent  import- 
ance, and  as  both  of  its  metals,  the  lead  and  silver,  arc  valuable  and 
the  reduction  easy,  it  is  worked  when  containing  but  five  ounces  of 
silver  to  the  ton. 

The  veins  of  silver  ores  in  gneiss  and  mctamorphic  rocks,  away 
from  eruptive  kinds,  usually ^ave_^^njte_as  the_chief  _pre,  with 
sulphides  of  iron,  zinc,  aifd  copper  as  associates,  and  quartz,  and 
often  more  or  less  fiuorite  or  barite,  as  the  ganguc.  Other"  silver 
ores,  the  sulphides,  arsenical  and  antimonial,  "m"ay~also  be  present 
and  abundant;  yet  when  so,  they  are  mostly  if  not  wholly  second- 
ary products,  and  are  accompanied  generally  by  lead  carbonate  and 
sulphate.  But  in  most  rich  silver  regions  tlic  veins,  whether  inter- 
secting metamorphic,  iragmental  or  calcareous  formations,  arc  con- 
nected with  eruptive  rocks.  -Yet  even  in  such  cases  galenite  is 
usually  an  abundant  vein-material,  and  may  have  been  a  source  of 
much  of  the  silver.  Sulphur,  arsenic,  and  antimony  have  been 
among  the  materials  introduced,  and  these  agents,  together  with  car- 
bonic acid,  phosphoric  acid,  oxygen  and  chlorine,  derived  from  below 
or  above,  have  carried  on  the  changes. 

The  silver-producing  veins  of  the  eastern  border  of  North  America 
are  mostly  veins  in  metamorphic  rocks  having  no  connection  with 
eruptive  rocks,  and  they  have  yielded  little  silver.  The  Michigan 
region  and  those  of  productive  mines  in  western  America  over  the  sum- 
mit and  western  slope  of  the  great  mountain  range  from  Patagonia 
to  British  America  arc  for  the  most  part  in  regions  intersected  by 
eruptive  rocks,  and  to  this  fact  owe  their  existence.  Moreover,  ex- 
cluding the  Michigan  region,  they  are  much  alike,  through  the  five 
thousand  miles,  in  their  characters,  their  ores,  and  the  associated 
eruptive  rocks.  The  eruptives  are  chiefly  andesytc,  rhyolyte,  dacytc, 
and  doleryte,  or  basalt.  Silver  chloride  is  usually  a  common  ore, 
especially  in  the  upper  part  of  the  veins  or  deposits;  and  a  mixture  of 
it  with  more  or  less  of  lead  carbonate,  often  with  iron  oxide  (from  the 
decomposition  of  iron  or  copper  sulphides)  and  with  limestone  and 
other  material  (from  the  decomposed  rocks),  makes  the  ore  called  car- 
bonate. Other  lead  ores,  the  ruby-silver  ores,  argentite,  stephanitc, 
tetrahedrite,  and  the  rest  of  those  above  enumerated,  are  common  in 
the  veins.  Gold  is  often  present,  also  copper  and  zinc  ores.  Lime- 
stone strata  are  common  repositories  of  the  ores;  and  this  is  attributed 
to~  the  fact  that  limestone  is  easily  eroded  "by  acid  solutions  and 
vapors;  so  that,  if  intersected  by  a  fissure  up  which  such  vapors  or 
solutions  arc  ascending,  cavities  or  chambers  will  be  made  in  it,  and 
passageways  along  the  joints  and  seams  for  the  reception  of  the  ore 
deposits.  In  the  AVashoe  region,  Nevada,  and  many  others,  there  is 


136  DESCRIPTIONS   OF   MINERALS. 

no  limestone.  The  chlorine  of  the  silver  chloride  is  supposed  to  have 
come  from  superficial  saline  waters,  like  those  of  the  Great  Salt  Lake, 
salt  Toeing" a  sodium  chloride;  carbonic  acid  for  the  lead  carbonate, 
from  the  limestone;  the  sulphur,  from  the  decomposition  of  sulphides, 
as  galenife,  pyiTte,  etc.;  the~arsenic,  antimony,  with  part  of  the  sul- 
phur, from  the  ascending  vapors;  the  sjlver,  from  ores  in  the  rock 
making  the  walls  of  the  fissures  somewhere  below  at  large  or  shallow 
depths" (and  argentiferous  galenitc  may  have  been  the  most  prominent 
source).  Secondary  products  are  still  in  progress  in  the  surface  por- 
tion of  most  veins;  and  in  the  deeper,  if  there  is  some  little  heat  to 
favor  change. 

The  richest  mines  of  Chili  are  not  far  distant  from  Copiapo,  in  the 
mountains  north  of  the  valley  of  Huasco.  The  mines  of  Mt.  Chanar- 
cillo,  about  16  leagues  south  of  Copiapo,  abound  in  horn  silver,  and 
begin  to  yield  arsenio-sulphides  at  a  depth  of  about  500  feet.  The 
mines  of  Punta  Brava,  which  are  nearer  the  Cordilleras,  afford  the 
arsenical  and  antimonial  ores.  In  Peru,  the  principal  mines  are  in 
the  districts  of  Pasco,  Chota,  and  Huantaya.  Those  of  Pasco  are 
15,700  feet  above  the  sea,  while  those  of  Huantaya  are  in  a  low  desert 
plain,  near  the  port  of  Yquique,  in  the  southern  part  of  Peru.  The 
ores  afforded  are  the  same  as  in  Chili.  The  mines  of  Huantaya 
are  noted  for  the  large  masses  of  native  silver  they  have  afforded. 
Silver  is  obtained  In  Peru,  also,  in  the  districts  of  Caxamarca,  Pataz, 
Huamanchuco,  and  Hualgayoc.  The  Potosi  mines  in  Bolivia  occur  in 
a  mountain  of  argillaceous  shale,  whose  summit  is  covered  by  a  bed 
of  argillaceous  porphyry.  The  ore  is  the  ruby  silver,  and  argentite 
with  native  silver.  The  district  of  Caracoles,  between  Chili  and 
Bolivia,  yields  much  silver. 

In  Europe  the  principal  mines  arc  those  of  Spain,  the  province 
of  Guadalajara,  where  the  ore  is  chiefly  freieslebenite;  of  Kongs* 
berg  in  Norway ;  of  Saxony,  chiefly  at  Freiberg,  Ehrenfriedens- 
clorf,  Jobanngeorgcnstadt,  Annaberg,  and  Schneeberg;  in  the  Hartz; 
in  Austria,  Hungary,  Transylvania,  and  the  Banat;  and  Russia,  The 
mines  of  Kongsberg,  in  Norway,  occur  in  gneiss  and  hornblende 
slate,  in  a  gangue  of  calcite.  They  were  especially  rich  in  native 
silver. 

In  the  Tyrol,  Austria,  argentite,  argentiferous  tetrahedrite,  and  mis- 
pickel  occur  in  a  gangue  of  quartz,  in  argillaceous  schist.  The  Hun- 
garian mines,  at  Schemnitz  and  Kremnitz,  occur  in  syeuyte  and  horn- 
blende porphyry,  in  a  gangue  of  quartz,  often  with  calcite  or  barite 
(heavy  spar),  and  sometimes  fluorite.  The  ores  are  argentite,  tetrahe- 
drite, galenite,  blende,  pyritous  copper  and  iron;  and  the  galenite  and 
copper  ores  are  argentiferous.  France  produces  some  silver  from  ar- 
gentiferous galenite  at  Huelgoet  in  Brittany,  and  the  mines  of  Pontgi- 
baud,  Puy-de-Dome. 

The  Russian  mines  are  in  Kolyvan  in  the  Altai,  and  Nertschinsk  in 
the  Daouria  Mountains,  Siberia  (east  of  Lake  Baikal).  The  Dapuria 
mines  afford  argentiferous  galenite  which  is  worked  for  its  silver; 
it  occurs  in  a  crystalline  lirneslone.  The  silver  ores  of  the  Altai  occur 
in  Silurian  schists  in  the  vicinity  of  porphyry,  which  contain  also 
gold,  copper,  and  lead  ores. 

The  mines  of  Mexico  are  most  abundant  between  18°  and  24°  north 


SILVER. 


137 


latitude,  on  the  back  or  sides  of  the  Cordilleras,  and  especially  the 
west  side;  and  the  principal  are  those  of  the  districts  of  Guanaxuato, 
Zacatecas,  Fresnillo,  Sombrerete,  Catorce,  Oaxaca,  Pachuca,  Real  del 
Monte,  Batopilas,  and  Tasco.  The  vein  of  Guanaxuato,  the  most 
productive  in  Mexico,  intersects  argillaceous  and  cnloritic  shale,  and 
porphyry;  it  affords  one  fourth  of  all  the  Mexican  silver.  The  Valen- 
dan  mine  is  the  richest  in  Guanaxuato.  The  Pachuca,  Real  del 
Monte,  and  Moro  districts  are  near  one  another. 

In  the  United  States  the  chief  silver  mines  are  in  Colorado,  Nevada, 
Utah,  NewTSTelaarrArizona,  Montana,  Idaho.  For  regions,  sec  List 
of  Localities,  beyond.  The  copper  mines  of  northern  Michigan  afford 
much  native  silver,  and  also-  the  native  gold  of  the  various  gold  mines 
of  the  country. 

For  the  years  previous  to  1859  the  whole  yield  of  silver  from  the 
United  States  mines  is  estimated  at  $1,000,000.  The  following  are 
the  amounts  for  the  succeeding  years  to  1870: 


1859 $100,000 

1860 150,000 

1861 2,100,000 

1862 4,500,000 

1863 8,500,000 

1864 11,000,000 


1865 $11,250,000 

1866 10,000,000 

1867 13,550,000 

1868 12,000,000 

1869 13,000,000 

1870 17,320,000 


The  Comstock  lode,  in  the  Washoe  region,  Nevada,  was  first  opened 
in  1859,  and  contributed  to  the  silver  of  the  world,  in  1860,  about 
$1,000,000.  Virginia  City  grew  out  of  it.  In  1861  other  mining 
regions  were  discovered  in  Humboldt  Co. ,  150  miles  north-east  of  Vir- 
ginia City,  and  in  1862  the  Reese  River  discoveries  (at  the  present  town 
of  Austin)  were  made;  others  soon  followed,  among  which,  those  in 
the  Eureka  district,  60  miles  east  of  Austin,  have'provcd  of  great 
value.  Nevada  Territory  in  1875  yielded  of  silver  $14,922,350,  and 
in  1876,  $20,570,078.  The  amount  fell  off  in  1878,  owing  to  the  work- 
ing out  of  the  Comstock  lode,  and  in  1882  it  was  only  $6,750,000. 

For  the  yield  of  the  United  States  in  silver  since  1870,  see  pace  127. 

The  yield  of  the  Western  States  and  Territories  in  1876  and  1884 
is  reported  as  follows: 

1884. 

$4,500.000 
3,000.000 
16,000,000 
150,000 
2,720.000 
7,000.000 
5,600,000 
3,000,000 
20.000 
6,800,000 
1,000 


1876. 

Arizona $500,000 

California 1,800,000 

Colorado 3,000,000 

Dakota 

Idaho 300,000 

Montana 800,000 

Nevada 20,570,078 

New  Mexico 400,000 

Oregon 

Utah 3,351,520 

Washington 


138 


DESCRIPTIONS   OF   MINERALS. 


In  the  Report  of  the  U.  S.  Mint  for  1885  the  yield  of  the  world 
in  1884  is  given  approximately,  as  follows: 

Norway  and  Sweden $340,962 

Austria-Hungary 2,054,070 

Germany , 10,311,659 

Russia 388,000 

France 264,275 

Italy 17.949 

Spain 148,000 

Turkey 89,916 

Australia 11 5,960 

Japan 877,772 

Peru 1,908,000 

Bolivia 16,000,000 

Chili 5,325,000 

Argentine  Republic 420,225 

Colombia 760,000 

Mexico 27,257,885 

United  States 48,800,000 

Canada 68,205 


Total $115,147,878 

The  following  table  gives,  in  dollars,  the  estimated  value  of  the 
world's  production  of  silver  in  recent  years: 


Russia. 

United  States. 

Mexico  and 
S.  America. 

Other 
Countries. 

Total. 

1855 

600  000 

30  000  000 

10  000  000 

40  600  000 

1860... 
1865... 
1870  .. 
1875... 
1882... 
1884... 

650,000 
700,000 
575.000 
500,000 
324,000 
383,000 

150,000 
11.250,000 
17,320,000 
31,635,000 
46,800,000 
48,800,000 

30,000,000 
30,000,000 
25,000,000 
25,000,000 
48,651,000 
51,740,000 

10,000,000 
10,000,000 
10.000.000 
10,000.000 
16.000.000 
14,222,000 

40,800.000 
51,950,000 
57,895,000 
67,135,000 
111,775,000 
115,150,000 

The  world's  production  of  silver  from  1800  to  1830  is  estimated  at 
$799,100.000  (average  $26,637,000);  from  1830  to  1851,  inclusive,  at 
$600,400.000  (average  $27,300,000);  from  1852  to  1877,  twenty-six 
years,  $1.341,800.000  (average  $51,608,000);  from  1882  to  1884,  in- 
clusive, $343,893,000  (average  $114,631,000). 

The  relative  value  of  silver  and  gold,  about  1500,  was  1: 11*25; 
1600,  1:12;  1700,  1:15;  1800,  1:15;  1820,  1:15'5:  1840,  1:1575; 
1860,  1:15-35;  1875,  1:16;  1878,  1:18;  1879,  1:18'4;  1886,  1:20. 
Herodotus  made  the  ratio  1:13;  Plato,  1:12;  Menander,  1:10;  and 
in  Caesar's  time  it  was  1 : 9. 


PLATINUM.  139 


Native  Platinum. 

Isometric:  but  crystals  seldom  observed.  Usually  in 
flattened  or  angular  grains  or  irregular  masses.  Cleavage 
none. 

Color  and  streak  pale  or  dark  steel-gray.  Lustre  metal- 
lic, shining.  Ductile  and  malleable.  H.  =  4-4*5.  G.  = 
16-19;  17-108,  small  grains;  17'608,  amass.  (When  pure, 
21-15.)  Often  slightly  magnetic,  and  some  masses  will 
take  up  iron  filings. 

Composition.  Platinum  is  usually  combined  with  more  or 
less  of  the  rare  metals  iridium,  rhodium,  palladium,  and 
osmium,  besides  copper  and  iron,  which  give  it  a  darker 
color  than  belongs  to  the  pure  metal  and  increase  its  hard- 
ness. A  Russian  specimen  afforded:  Platinum  78*9,  iri- 
dium 5-0,  osmium  and  iridium  1*9,  rhodium  0*9,  palladium 
0-3,  copper  0-7,  iron  11-0  =  98-75.  California  platinum 
afforded:  Platinum  85*50,  iridium  1*05,  osmiridium  1*10, 
rhodium  I'OO,  palladium  0-60,  copper  1*40,  iron  6'75  ;  but 
some  of  California  yields  only  50  per  cent,  of  platinum. 

Platinum  is  soluble  in  heated  aqua  regia.  It  is  one  of 
the  most  infusible  substances  known,  being  B.B.  unaltered. 
Slightly  magnetic,  and  this  quality  is  increased  by  the  iron 
it  may  contain. 

Diff.  Platinum  is  at  once  distinguished  by  its  malleability, 
specific  gravity,  and  extreme  infusibility. 

Obs.  Platinum  was  first  detected  in  1735  in  grains  in  the 
alluvial  deposits  of  Choco  and  Barbac.oa  in  New  Granada 
(now  U.  States  of  Colombia),  within  two  miles  of  the  north- 
west coast  of  South  America,  where  it  received  the  name 
platina,  derived  from  the  word  plata,  meaning  silver.  Al- 
though before  known,  an  account  by  Ulloa,  a  Spanish 
traveller  in  America  in  1735,  directed  attention  in  Europe, 
in  1748,  to  the  metal.  It  is  now  obtained  in  No  vita,  and 
at  Santa  Rita  and  Santa  Lucia,  Brazil.  It  has  been  af- 
forded most  abundantly  by  the  Urals.  It  occurs  also  on 
Borneo ;  in  the  sands  of  the  Rhine ;  in  Australia ;  in 
those  of  the  river  Jocky,  St.  Domingo  ;  in  traces  in  the 
U.  States,  in  Rutherford  Co.,  N.  Carolina;  Virginia; 
Georgia ;  at  La  Francois  Beauce,  Canada  ;  with  gold  near 
Point  Orf ord,  on  the  coast  of  Northern  California  (probably 
derived,  according  to  W.  P.  Blake,  from  serpentine  rocks); 
Wood  R.  Co.,  Idaho;  in  British  Columbia.  A  nugget,  of 


140  DESCRIPTIONS   OF   MINERALS. 

104*4  grams,  found  near  Plattsburgh,  N".  Y.,  afforded  Col- 
lier 46  p.  c.  of  platinum  and  54  p.  c.  of  chromite,  and  had 
G.  =10-446. 

The  Ural  localities  of  Nischne  Tagilsk  and  Goroblagodat 
have  afforded  much  the  larger  part  of  the  platinum  of  com- 
merce. It  occurs,  as  elsewhere,  in  alluvial  beds ;  but  the 
courses  of  platiniferous  alluvium  have  been  traced  to  a  great 
extent  up  Mount  La  Martiane,  which  consists  of  crystalline 
rocks,  and  is  the  origin  of  the  detritus.  One  to  three  pounds 
are  procured  from  3700  pounds  of  sand.  The  production 
of  the  U.  States  in  1884  was  not  over  150  troy  ounces. 

Though  commonly  in  small  grains,  masses  of  considerable 
size  have  occasionally  been  found.  A  mass  weighing  1088 
•grains  was  brought  by  Humboldt  from  South  America  and 
deposited  in  the  Berlin  Museum.  Its  specific  gravity  was 
18 '94.  In  the  year  1822,  a  mass  from  Oondoto  was  de- 
posited in  the  Madrid  Museum,  measuring  2  inches  and  4 
lines  in  diameter,  and  weighing  11,641  grains.  A  more 
remarkable  specimen  was  found  in  the  year  1827  in  the 
Urals,  not  far  from  the  Demidoff  mines,  which  weighed 
11-57  pounds  troy;  and  similar  masses  are  now  not  uncom- 
mon. The  largest  hitherto  discovered  weighed  21  po.unds 
troy. 

Eussia  has  afforded  annually  about  35  cwt.  of  platinum, 
which  is  about  five  times  the  amount  from  Brazil,  Borneo, 
Colombia,  and  St.  Domingo.  Borneo  affords  about  500 
pounds  per  year. 

The  infusibility  of  platinum  and  its  resistance  to  the  ac- 
tion of  the  air,  and  moisture,  and  most  chemical  agents, 
renders  it  of  great  value  for  the  construction  of  chemical 
and  philosophical  apparatus.  The  large  stills  employed  in 
the  concentration  of  sulphuric  acid  are  now  made  of  plati- 
num ;  but  such  stills  are  gilt  within,  since  platinum  when 
unprotected  is  acted  upon  by  the  acid,  and  soon  becomes 
porous.  It  is  also  used  for  crucibles  and  capsules  in  chemi- 
cal analysis ;  for  galvanic  batteries ;  as  foil,  or  worked  into 
cups  or  forceps,  for  supporting  objects  before  the  blowpipe. 
It  alloys  readily  when  heated  with  iron,  lead,  and  several  of 
the  metals,  and  is  also  attacked  by  caustic  potash  and  phos- 
phoric acicl,  in  contact  with  carbon ;  and  consequently  there 
should  be  caution  when  heating  it  not  to  expose  it  to  these 
agents. 

It  is  employed  for  coating  copper  and  brass;  also  for 


PALLADIUM.  141 

gainting  porcelain  and  giving  it  a  steel  lustre,  formerly 
ighly  prized.  It  admits  of  being  drawn  into  wire  of  ex- 
treme tenuity. 

Platinum  was  formerly  coined  in  Russia.  The  coins  had 
the  value  of  11  and  22  rubles  each.  /  t^t^U.  • 

This  metal  fuses  readily  before  the  "  compound  blow- 
pipe •"  and  Dr.  Hare  succeeded  in  1837  in  melting  tventy- 
eight  ounces  into  one  mass.  The  metal  was  almost  as  mal- 
leable and  as  good  for  working  as  that  obtained  by  the  other 
process  ;  it  had  a  specific  gravity  of  19 '8.  He  afterwards 
succeeded  in  obtaining  from  the  ore  masses  which  were  90 
per  cent,  platinum,  and  as  malleable  as  the  metal  in  ordinary 
use,  though  somewhat  more  liable  to  tarnish,  owing  to  some 
of  its  impurities.  Deville  and  Debray  have  perfected  this 
process,  and  have  melted  over  25  pounds  of  platinum  in  less 
than  three  quarters  of  an  hour.  In  the  process  the  osmium 
present  is  oxidized  and  thus  removed. 

Platin-iridium.  Grains  of  iridium  have  been  obtained  at  Nischne 
Tagilsk,  consisting  of  76'8  iridium  and  19'64  platinum,  with  some 
palladium  and  copper.  A  similar  platin-iridium  has  been  obtained  at 
Ava,  in  the  East  Indies.  Another,  from  Brazil,  contained  27*8  iridium, 
55*5  platinum,  and  6'9  rhodium.  Reported  from  Mendocino  and 
Trinity  Cos.,  Cal. 

Iridosmine.  A  compound  of  iridium  and  osmium  from  the  platinum 
mines  of  Russia,  South  America,  the  East  Indies,  and  California  ;  in 
pale  steel-gray  hexagonal  prisms,  but  usually  in  fiat  grains  ;  H.  —  6*7  ; 
G.  =  19-5-21-1 ;  malleable  with  difficulty.  One  variety,  called  Nef- 
danskite,  contains  iridium  46'8,  osmium  49'3,  rhodium  3'3,  iron  0'7. 
Another,  Sisserskite,  iridium  25'1,  osmium  74  9,  and  iridium  20,  os- 
mium 80.  But  analysis  affords  also  from  0'5  to  12'3  of  rhodium,  and 
0'2  to  6'4  of  the  rarer  metal  ruthenium,  with  traces  usually  of  plati- 
num, copper,  and  iron.  The  grains  are  distinguished  from  those  of 
platinum  by  their  superior  hardness,  and  also  by  the  peculiar  odor  of 
osmium  when  heated  with  nitre.  Iridosmine  is  common  with  the  gold 
of  Northern  California,  and  injures  its  quality  for  jewelry.  Occurs 
sparingly  in  the  gold  washings  on  the  rivers  Du  Loup  and  Des 
Plantes,  Canada. 

The  metal  iridium  is  extremely  hard,  and  is  used,  as  well  as  rhodium, 
for  points  to  the  nibs  of  gold  pens,  for  the  knife-edges  of  fine  balances, 
etc.  The  standard  meters  of  the  International  Commission  on  Weights 
and  Measures  consist  of  90  per  cent,  of  platinum  and  10  of  iridium. 

Laurite.  In  minute  octahedrons.  A  ruthenium  sulphide,  with  3 
per  cent,  of  osmium.  From  platinum  sands  of  Borneo  and  Oregon. 

Palladium. 

Isometric.  In  minute  octahedrons.  Occurs  mostly  in 
grains,  sometimes  composed  of  divergent  fibres.  Color 


142  DESCRIPTIONS   OF   MINERALS. 

steel-gray,  inclining  to  silver-white.  Ductile  and  malle- 
able. H.  =  4-5-5.  G.  =  1I'3-12'2  (the  latter  after  ham- 
mering). 

Consists  of  palladium,  with  some  platinum  and  iridium. 
Fuses  with  sulphur,  but  not  alone. 

Obs.  Occurs  in  Brazil  with  gold,  and  is  distinguished 
from  platinum,  with  which  it  is  associated,  by  the  divergent 
structure  of  its  grains.  It  was  discovered  by  Wollaston,  in 
1803.  Selenpalladite,  or  Allopalladiwn,  is  from  Tilkerode 
in  the  Hartz;  reported  also  from  St.  Domingo  and  the  Urals. 
Porpezite  is  palladium  gold,  or  gold  containing  7  to  11  per 
cent,  of  palladium. 

This  metal  is  malleable,  and  when  polished  has  a  whitish 
steel-like  lustre  which  does  not  tarnish.  A  cup  weighing 
3^  pounds  was  made  by  M.  Breant  in  the  mint  at  Paris,  and 
is  now  in  the  garde-meuble  of  the  French  crown.  In  hard- 
ness it  is  equal  to  fine  steel.  1  part  fused  with  6  of  gold 
forms  a  white  alloy  ;  and  this  compound  was  employed,  at 
the  suggestion  of  Dr.  Wollaston,  for  the  graduated  part  of 
the  mural  circle  constructed  by  Trough  ton  for  the  Royal 
Observatory  at  Greenwich.  Palladium  has  been  employed 
also  for  certain  surgical  instruments. 

MERCURY. 

I  \ 

Mercury  occurs  native;  alloyed  with  silver  forming  na- 
tive amalgam;  in  combination  with  sulphur,  selenium, 
chlorine,  or  iodine;  and  with  sulphur  and  antimony  in  some 
tetrahedrite.  Its  ores  are  completely  volatile,  excepting 
when  silver  or  copper  is  present. 

Native  Mercury,  or  Quicksilver. 

Isometric.  In  fluid  globules  scattered  through  the 
gangue.  Color  tin- white.  G.  when  pure  =  13*58.  Be- 
comes solid  and  crystallizes  at  a  temperature  of  —  39°  F., 
and  then  G.  =.14;4-14-5. 

Mercury,  or  quicksilver,  as  it  is  often  called  (a  transla- 
tion of  the  old  name  "argentum  vivum"),  is  entirely 
volatile  B.B.,  and  dissolves  readily  in  nitric  acid. 

Obs.  Occurs  at  the  different  mines  of  this  metal,  at 
Almaden  in  Spain,  Idria  in  Carniola  (Austria),  in  Hungary, 
Peru,  California,  and  Colorado.  Usually  in  disseminated 


MERCURY.  143 

globules,  but  sometimes  accumulated  in  cavities  so  as  to  be 
dipped  up  in  pails. 

Used  for  the  extraction  of  gold  and  silver  ores.  Also 
employed  for  silvering  mirrors,  for  thermometers  and 
barometers,  and  for  various  purposes  connected  with  medi- 
cine and  the  arts. 

Native  Amalgam.    Sec  page  130. 
fyQ  Cinnabar. — Mercury  Sulphide. 

Rhombohedral ;  R  A  R  =  72°  36' .  Cleavage  lateral,  high- 
ly perfect.  Crystals  often  tabular,  or  six-sided  prisms. 
Also  massive;  sometimes  in  earthy  coatings. 

Lustre  unmetallic,  of  crystals  adamantine  ;  often  dull. 
Color  bright  red  to  brownish  red,  and  brownish  black. 
Streak  scarlet-red.  Subtransparent  to  nearly  opaque. 
H.  =  2-2-  5.  G.  =  9  ;  impure,  8*5  and  less.  Sectile. 

Composition.  HgS2  =  Sulphur  13 '8,  mercury  86 '3. 
Often  impure.  The  liver  ore,  or  hepatic  cinnabar,  contains 
some  carbon  and  clay,  and  has  a  brownish  streak  and  color. 
B.B.  volatilizes  entirely  when  pure. 

Diff.  Distinguished  from  red  oxide  of  iron  and  chromate 
of  lead  by  vaporizing  B.  B. ;  from  realgar  by  alliaceous  fumes 
on  charcoal. 

Obs.  The  ore  from  which  the  principal  part  of  the  mer- 
cury of  commerce  is  obtained.  When  pure  identical  with 
the  pigment  vermilion.  Occurs  mostly  in  connection  with 
siliceous,  hydromica,  and  argillaceous  slates,  or  other  stra- 
tified deposits,  both  the  most  ancient  and  those  of  more 
recent  date.  Too  volatile  to  be  expected  in  any  abundance 
in  proper  igneous  or  highly  crystalline  rocks,  yet  has  been 
found  sparingly  in  granite. 

The  localities  are  mentioned  beyond. 

Metacinnabarite.  The  same  compound  as  cinnabar,  but  different 
in  crystallization.  Redington  Mine,  Lake  Co.,  Cal.  Guadalcazarite, 
from  Mexico,  is  a  variety. 

Tiemannite.  Dark  steel-gray  mercury  selenitic.  The  Hartz ; 
vicinity  of  Clear  Lake,  Cal.,  and  Utah. 

Onofrite.  Massive,  blackish-gray,  metallic  ;  G.  —  7'62  ;  mercury 
sulpho-selenide.  San  Onofrc,  Mexico;  Marysyale,  Utah. 

Coloradoite.  Grayish-black  mercury  telluride ;  G.  =  8'627.  Key- 
stone and  Mountain  Lion  and  Smuggler  Mines,  Col. 

Calomel  or  Horn  Quicksilver.  Mercury  chloride;  tough,  sectile ; 
light  yellowish  or  grayish ;  lustre  adamantine;  translucent  or  sub- 


144  DESCRIPTIONS   OF   MINERALS. 

translucent;  H.  =  1-2;  G.  =  6*48;  contains  15'1  per  cent,  of  chlo- 
rine and  84 '9  of  mercury.  Spain. 

lodic  Mercury.    Mercury  iodide;  reddish  brown.     Mexico. 

Mannolite.  Mercury  tcllurale,  in  white,  silky  radiating  tufts ; 
Hg2O4Te.  Magnolia  District,  Col. 

Barcenite.  Gray  to  black,  earthy  lustre  ;'H.  =  5'5  ;  G.  =  5 '343  ; 
an  antimonate  containing  20'75  per  cent,  of  mercury.  Mexico. 

General  Remarks. — The  following  are  the  regions  of  the  principal 
mines  of  mercury.  At  Idria,  in  Austria  (discovered  in  1497),  where 
the  ore  is  a  dark  bituminous  cinnabar  distributed  through  a  blackish 
shale  or  slate,  containing  some  native  mercury  ;  at  Almaden,  in  Spain, 
near  the  frontier  of  Estremadura,  in  the  province  of  La  Mancba,  in 
argillaceous  beds  and  grit  rock,  which  are  intersected  by  dikes  of 
"  black  porphyry"  and  granite — mines  mentioned  by  Pliny  as  afford- 
ing vermilion  to  the  Greeks,  700  years  before  the  Christian  era ;  in 
the  Palatinate  on  the  Rhine;  in  Hungary;  Sweden;  France;  Ripa, 
in  Tuscanv ;  region  of  the  Don,  in  Russia :  in  Shensi,  in  China ;  at 
Arqueros,  in  Chili ;  at  Huanca  Velica,  and  some  other  points  in  Peru ; 
at  St.  Onofre  and  other  places  in  Mexico  ;  in  California. 

The  most  noted  of  the  California  mines,  New  Almaden,  is  situated 
in  Mine  Hill,  Santa  Clara  Co.,  south  of  San  Francisco.  The  rocks 
are  altered  Cretaceous  slates,  talcose  in  part,  with  beds  of  serpentine 
either  side,  and  associated  also  with  beds  of  jasper  or  siliceous  slate. 
The  New  Idria  mine  is  in  Fresno  Co.,  in  the  Mt.  Diablo  Range,  and 
was  discovered  in  1855.  The  rocks  are  more  or  less  altered  silico- 
argillaceous  and  siliceous  slates  and  sandstones,  and  the  cinnabar  is 
distributed  irregularly  through  them ;  between  this  and  the  Aurora 
Mine  on  San  Carlos  (the  highest  peak  of  the  Diablo  Range,  4977  feet), 
there  is  much  serpentine  (in  which  is  chromic  iron)  and  siliceous  rock 
or  slate.  In  Napa  Valley,  Napa  Co.,  north  of  San  Francisco,  there 
are  other  valuable  mines  situated"  in  rocks  closely  similar,  as  Whitney 
states,  to  those  affording  quicksilver  at  New  Almaden.  They  are  in 
a  serpentine  belt,  the  cinnabar  being  in  some  places  in  the  serpentine, 
but  mostly  in  the  peculiar  siliceous  rock  associated  with  it.  Native 
mercury  occurs  with  the  cinnabar.  There  are  mines  also  in  Lake  Co. 

The  product  of  the  California  mines  of  mercury  in  1874  was  34,254 
flasks  (a  flask  in  California  =  76£  IDS),  or  over  2,600,000  Ibs.;  in  1881, 
60,851  flasks;  in  1884,  31,913  flasks.  About  two  thirds  of  the  amount 
in  1884  was  from  the  New  Almaden  mine.  The  yield  of  the  Almaden 
mine,  Spain,  in  1884,  was  about  43,100  flasks,  and  that  of  the  Idria' 
mine,  Austria,  13,000.  The  other  foreign  mines  produce  but  little. 
The  price  in  1884  was  20  to  35  dollars  per  flask,  or  34  to  46  cents  per 
pound. 

COPPER. 

.Copper  occurs  native;  also  combined  with  oxygen,  sul- 
phur, selenium,  arsenic,  antimony,  chlorine;  and  as  carbon- 
ate, phosphate,  arsenate,  nitrate,  sulphate,  vanadate,  and 
silicate.  The  ores  of  copper  vary  in  specific  gravity  from 
3 '5  to  8 '5,  and  seldom  exceed  4  in  hardness. 


COPPER.  145 

Native   Copper. 

Isometric.  In  octahedral,  dodecahedral,  and  other 
forms,  often  much  distorted  ;  no  cleavage  apparent.  Also 
in  plates  or  masses,  and  in  large  or  small  arborescent  and 
filiform  shapes,  consisting  usually  of  a  string  of  crystals. 

Color  copper-red.  Ductile  and  malleable.  H.  =2 '5-3. 
G.  =8-8-8-95;  when  pure  8*91-8  95. 

Often  contains  a  little  disseminated  silver.  B.  B.  fuses 
readily,  and,  on  cooling,  covered  with  the  black  oxide. 
Dissolves  in  nitric  acid,  and  produces  a  deep  azure-blue 
solution  on  the  addition  of  ammonia.  Fuses  at  1930°  F. 

Obs.  Native  copper  accompanies  ores  of  copper,  and  usually 
occurs  in  the  vicinity  of  dikes  of  igneous  rocks. 

Siberia,  Cornwall,  and  Brazil  are  noted  for  the  native 
copper  they  have  produced.  A  mass,  supposed  to  be  from 
Bahia,  now  at  Lisbon,  weighs  2616  pounds.  South  of  Lake 
Superior  about  Portage  Lake  on  Keweenaw  Point,  and  also, 
less  abundantly,  on  the  Ontonagon  River,  and  at  some  other 
points  in  that  region,  native  copper  occurs  mostly  in  veins 
in  trap,  and  also  in  the  enclosing  sandstone.  A  mass 
weighing  37041bs.  has  been  taken  from  thence  to  Washing- 
ton City  ;  it  is  the  same  that  was  figured  by  Schoolcraft,  in 
the  American  Journal  of  Science,  volume  iii.,  p.  201.  One 
large  mass  was  quarried  out  in  the  "Cliff  Mine,"  whose 
weight  has  been  estimated  at  200  tons.  It  was  40  feet  long, 
6  feet  deep,  and  averaged  6  inches  in  thickness.  This  cop- 
per contains,  intimately  mixed  with  it,  about  T3^  per  cent, 
of  silver.  Besides  this,  perfectly  pure  silver,  in  strings, 
masses,  and  grains,  is  often  disseminated  through  the  cop- 
per, and  some  masses,  when  polished,  appear  sprinkled  with 
large  white  spots  of  silver,  "resembling  a  porphyry  with  its 
feldspar  crystals."  Crystals  of  native  copper  are  also  found 
penetrating  masses  of  prehnite  and  analcite  in  the  trap  rock. 
This  mixture  of  copper  and  silver  cannot  be  imitated  by 
art,  as  the  two  metals  form  an  alloy  when  melted  together. 
It  is  probable  that  the  separation  in  the  rocks  is  due  to 
the  cooling  from  fusion  being  so  extremely  gradual  as  to 
allow  the  two  metals  to  solidify  separately,  at  their  respec- 
tive temperatures  of  solidification— the  trap  being  an  igneous 
rock,  and  ages  often  elapsing,  as  is  well  known,  during  the 
cooling  of  a  bed  of  lava  when  covered  from  the  air.  Native 
copper  occurs  sparingly  on  St.  Ignace  and  Michipicoten 
Islands,  Lake  Superior. 
10 


146  DESCRIPTIONS   OF   MINERALS. 

Small  specimens  of  native  copper  have  been  found  in  the 
States  of  New  Jersey,  Connecticut,,  and  Massachusetts, 
where  the  Triassic  formation  occurs.  One  mass  from  near 
Somerville,  N.  J.,  weighs  78  pounds,  and  is  said  originally 
to  have  weighed  128  pounds.  Within  a  few  miles  to  the 
north  of  New  Haven,  Conn.,  one  mass  of  90  pounds,  and 
another  of  200,  besides  other  smaller,  have  been  found  in 
the  drift,  all  of  which  came  from  veins  in  the  trap  or  asso- 
ciated Triassic  sandstone. 

Native  copper  occurs  also  in  South  Australia  ;  it  is  stated 
that  a  single  train  from  the  Moonta  Mine  carried  away  at 
one  time  forty  tons  of  native  copper. 

SULPHIDES,  SELENIDES,  ARSENIDES. 
Ohalcocite. — Copper  Glance.    Vitreous  Copper  Ore.     Eedruthite. 

Orthorhombic;  /:  /=  119°  35'.  Cleavage  parallel  to  /, 
but  indistinct.  Also  in  compound  crystals 
like  aragonite.  Often  massive. 

Color  and  streak  blackish  lead-gray  ; 
often  tarnished  blue  or  green.  Streak 
sometimes  shining.  H.  =  2 '5-3.  G.  = 
5-5-5-8. 

Composition.  Cu2S  =  Sulphur  20*2, 
copper  79 -8  =  100.  B.B.  on  charcoal  gives 
off  fumes  of  sulphur,  fuses  easily  in  the 
exterior  flame ;  and  after  the  sulphur  is 
driven  off,  a  globule  of  copper  remains. 
Dissolves  in  heated  nitric  acid,  with  a  pre- 
cipitation of  the  sulphur. 

Diff.  Resembles  argentite,  but  is  not  sectile,  and  affords 
different  results  B.B.  The  solution  in  nitric  acid  covers 
an  iron  plate  (or  knife-blade)  with  copper,  while  a  similar 
solution  of  the  silver  ore  covers  a  copper  plate  with  silver. 

Obs.  Occurs  with  other  copper  ores  in  beds  and  veins. 
At  Cornwall,  splendid  crystallizations ;  also  in  Siberia; 
Hesse;  Saxony;  the  Banat;  Chili,  etc. 

In  the  United  States,  a  vein  formerly  affording  fine  crys- 
tallizations occurs  at  Bristol,  Ct.  Other  localities  are  at 
Wolcottville,  Simsbury,  and  Cheshire,  Ct.;  at  Schuyler's 
Mines,  and  elsewhere,  N.  J. ;  in  the  U.  S.  copper-mine  dis- 
trict, Blue  Ridge,  Orange  County,  Va.;  between  New 
Market  and  Taneytown,  Md. ;  and  sparingly  at  the  copper 


COPPER.  147 

mines  of  Michigan  and  the  Western  States;  also  at  some 
mines  north  of  Lake  Huron ;  in  the  San  Juan  and  other 
mining  regions  in  Colorado;  in  New  Mexico,  in  Socorro  and 
Grant  Cos.;  in  Arizona;  at  the  Bruce  Mines,  Lake  Huron, 
and  at  Prince's  Mine,  Spar  Island,  and  on  Michipicoten 
Island,  Lake  Superior. 

Covellite,  or  Slue  Copper.      Massive;  dull  blue-black;  the  composi- 
tion CuS;  G.  —  3  8;  contains  66 '5  per  cent  of  copper. 
Harrisite.    Chalcocite  with  cubic  cleavage.     Canton  Mine,  Ga. 

Chalcopyrite. — Copper  Pyrites.     Copper  and-Iron  Sulphide. 

Tetragonal;   1  A  1  =  109°  53',  and   108°  40'.      Crystals 
tetrahedral  or  octahedral;  sometimes 
compound.  Cleavage  indistinct.  Also 
massive,    and    of    various    imitative 
shapes. 

Color  brass-yellow,  often  tarnished 
deep  yellow,  and  also  iridescent. 
Streak  unmetallic,  greenish  black, 
and  but  little  shining.  H.  =  3  "5—4. 
G.  =  415-4;3. 

Composition.  CuFeS2  =  Sulphur 
34-9,  copper  34'6,  iron  30*5  =  100.  Fuses  B.B.  to  a  mag- 
netic globule;  gives  sulphur  fumes  on  charcoal.  With  soda 
on  charcoal,  a  globule  of  metallic  iron  with  copper.  The 
usual  effect  with  nitric  acid. 

Diff.  Resembles  native  gold  in  color,  and  also  pyrite. 
Distinguished  from  gold  by  crumbling  under  a  knife,  instead 
of  separating  in  slices;  and  from  pyrite  in  its  deeper  yellow 
color,  and  in  yielding  easily  to  the  point  of  a  knife,  instead 
of  striking  fire  with  a  steel. 

Obs.  Occurs  in  veins  intersecting  gneiss  and  other  meta- 
morphic  rocks;  also  in  those  connected  with  eruptive  rocks; 
and  sometimes  in  cavities  or  veins  in  ordinary  stratified 
rocks.  Usually  associated  with  pyrite,  and  often  with  galen- 
ite,  blende,  and  copper  carbonates.  The  copper  of  Fahlun, 
Sweden,  is  obtained  mostly  from  this  ore,  where  it  occurs 
with  serpentine  in  gneiss.  Other  mines  of  this  ore  are  in 
the  Hartz,  near  Goslar;  in  the  Banat,  Hungary,  Thuringia, 
etc.  The  Cornwall  ore  is  mostly  of  this  kind.  As  prepared 
for  sale  at  Redruth  it  rarely  yields  12  per  cent.,  and  gene- 
rally only  7  or  8,  and  occasionally  as  little  as  3  to  4  per  cent. 


148  DESCRIPTIONS   OF   MINERALS. 

of  metal;  "6£  per  cent,  of  metal  may  be  considered  an 
average  of  the  produce  of  the  total  quantity  of  ore  sold." 
(Phillips,  1874.)  Such  poverty  of  ore  is  only  made  up  by 
its  facility  of  transport,  the  moderate  expense  of  fuel,  or 
the  convenience  of  smelting.  Its  richness  may  generally 
be  judged  of  from  the  color:  if  of  a  fine. yellow  hue,  and 
yielding  readily  to  the  hammer,  it  is  a  good  ore;  but  if  hard 
and  pale  yellow  it  contains  much  pyrite,  and  is  of  poor 
quality. 

In  the  U.  States  it  occurs  at  Ely  and  Stratford,  Vt. ;  at 
Shrewsbury,  Corinth,  Waterbury,  Vt. ;  also  in  New  Hamp- 
shire, Maine,  Massachusetts,  and  Connecticut;  at  the  An- 
cram  lead  mine,  N.  Y. ;  also  near  Rossie,  and  at  Wurtz- 
boiV,  N.  Y.;  at  Morgantown,  Pa.;  at  the  Phenix  copper 
mines,  Fauquier  Co  ,  and  at  the  Walton  gold  mine,  Lu- 
zerne  Co.,  \7a.;  Liberty  and  New  London  in  Frederick 
Co.,  at  the  Patapsco  mines  near  Sykesville,  Md.;  in  David- 
son and  Gruilford  Cos.,  N.  0.  In  Michigan,  where  native 
copper  is  so  abundant,  a  rare  ore;  occurs  at  Presqu'isle,  and 
at  Mineral  Point,  in  Wisconsin,  where  it  is  the  predomi- 
nating ore;  in  Polk  Co.,  at  the  Hiwassee  mines,  Tenn.;  in 
the  San  Juan  mining  region,  Col.;  in  Lander  Co.,  and 
elswhere,  Nev. ;  in  New  Mexico;  Arizona;  Idaho;  Utah;  at 
Copperopolis,  Calaveras  Co.,  Cal.;  also  at  the  Bruce  and 
other  mines  on  Lake  Huron;  and  Michipicoten  Islands,  in 
Lake  Superior.  ^ 

Cubanite  is  a  copper-and  iron  sulphide,  containing  Sulphur  39*0, 
Iron  38 '0,  copper  19 -8,  silica  2'3  =  99' 12.  Cuba. 

Bornite. — Erubescite,    Variegated  Copper  Pyrites. 

Isometric;  in  octahedrons  and  dodecahedrons.  Cleav- 
age octahedral  in  traces.  Also  massive. 

Color  between  copper-red  and  pinchbeck-brown;  but 
tarnishes  rapidly  on  exposure.  Streak  pale  grayish  black 
and  but  slightly  shining.  Brittle.  H.  =3.  G.  =  4-4-5 -5. 

Composition.  Cu3FeS3  =  Sulphur  28 '6,  copper  55 -58, 
iron  16-36  ;  but  varies  much.  The  ore  of  Bristol,  Ct.,  af- 
forded Sulphur  25-83,  copper  61-79,  iron  11-77  =  99-39. 

B.B.  on  charcoal  fuses  to  a  brittle  globule  attractable  by 
the  magnet ;  dissolves  in  nitric  acid,  with  separation  of 
sulphur. 

Diff.     Distinguished  from  the  preceding  by  its  pale  red- 


COPPER.  149 

dish-yellow  color,  and  its  rapidly  tarnishing  and  becoming 
of  bluish  and  reddish  shades  of  color,  the  quality  to  which 
the  name  erubescite,  from  the  Latin  word  for  to  blush,  al- 
ludes. 

Obs.  Occurs,  with  other  copper  ores,  in  granitic  and  al- 
lied rocks,  and  also  in  stratified  formations.  The  mines  of 
Cornwall  have  afforded  crystallized  specimens,  and  it  is 
there  called,  from  its  color,  "horse-flesh  ore."  Other  for- 
eign localities  of  massive  varieties  are  Ross  Island,  Killar- 
ney,  Ireland;  Norway,  Hessia,  Silesia,  Siberia,  and  the 
Banat. 

Fine  crystallizations  were  formerly  obtained  at  the  Bris- 
tol copper  mine,  Ct.,  in  granite ;  and  also  in  red  sandstone, 
at  Cheshire,  in  the  same  State,  with  malachite  and  barite. 
Massive  varieties  occur  at  the  New  Jersey  mines,  and  in 
Pennsylvania. 

Crookestte.  Copper  selenide  containing  17 '25  per  cent,  of  thallium, 
and  a  little  silver.  Norway. 

Domeykite.  White  to  pinchbeck  brown  metallic;  H.  =  3-3*5;  G.  = 
7-7-5;  copper  arsenide,  Cu3As2  =  Arsenic  28'3,  copper  71 '7  =  100. 
Chili;  Portage  Lake;  Michipicoten  Island,  L.  Superior.  Algodonite  ia 
Cu6As2.  Whitneyite  is  Cu9As2,  and  is  from  Houghton  Co.,  Mich.; 
Sonora. 

Bcrzelianite  is  a  copper  selenide;  Eucairite,  a  copper-and-silver 
selenide. 

SULPHARSENITES,  SULPHANTIMONITES,  AND  SULPHOBISMUTHITES. 

These  species  include— of  SULPHARSENITES:  Enargite,  Binnite, 
Tennantite,  Lautite,  Clarite,  Xanthoconite  ;  of  SULPHANTIMONITES  : 
Tetrahedrite,  Polybasite  (p.  133),  Chalcostibite,  Guejwrite,  Stylotypite, 
Bournonite  (Wheel  Ore),  Famatinile ;  of  SULPHOBISMUTHITES:  Aik- 
inite  (p.  164),  Emplectite,  Chimatiie,  Wittichenite. 

Enargite.  Orthorhombic;  grayish  iron-black;  H.  =3;  G.  =  4*34- 
4'45;  never  fibrous;  contains  46-50  p.  c.  of  copper.  Morococha, 
Peru;  Chili  (Ouayacanite}\  Brewster's  gold  mine,  S.  C.;  Morning 
Star  mine,  Alpine  Co.,  Cal.;  in  Gilpin  and  San  Juan  Cos.,  Col. 

Famatinite,  from  Peru  and  Arg.  Republic,  is  an  antimonial  enargite 
in  composition;  color  grayish  copper-red;  G.  —  4'57. 

Binnite.    In  isometric  crystals.     Valley  of  Binnen. 

Tennantite.  In  dodecahedrons;  color  and  streak  lead-gray  to  iron- 
black;  contains  some  iron  with  the  copper.  Cornwall;  Norway;  Cap- 
elton,  Quebec. 

Frederwite  is  a  variety  from  Sweden,  containing  2 '87  p.  c.  of  silver; 
and  Sandbergerite,  one  containing  zinc,  from  Peru. 


150  DESCRIPTIONS   OF   MINERALS. 

Tetrahedrite.    Gray  Copper.     Fahlerz. 

Isometric;  in  tetrahedral  crystals.  Steel-gray  to  blackish, 
and  streak  nearly  the  same,  to  brown  and  cherry-red.  H.  = 
3-4*5.  GL  =  4*7—5;  but  the  mercuriferous,  5*1-5*6. 

Composition.  4CuS  -f  Sb2S3.  Part  of  the  copper  often 
replaced  by  iron  and  zinc,  and  some- 
times by  silver  or  mercury,  and  part 
of  the  antimony  by  arsenic,  or  rarely 
bismuth ;  the  argentiferous  (Frei- 
bergite)  sometimes  contains  30  p.  c. 
of  silver,  and  the  mercuriferous 
(Schwatziie)  15  to  18  p.  c.  of  mer- 
cury; a  kind  from  Spain  contained 
10  p.  c.  of  platinum,  and  one  from 
Hohenstein  some  gold ;  another 
(named  Mali  now  skite)  9  to  13  p.  c.  of  lead  and  10  to  13  of 
silver.  The  Arkansas  mineral  afforded  on  analysis,  Sul- 
phur 26*71,  antimony  26-50,  arsenic  1*02,  copper  36-40, 
iron  1-89,  zinc  4*20,  silver  2 -30  =  99-02. 

From  Cornwall;  Andreasberg,  Hartz;  Kremnitz,  Hun- 
gary; Freiberg,  Saxony;  Kapnik,  Transylvania;  Dillen- 
burg,  Nassau;  Huallanca,  Peru,  at  a  height  of  14,700  feet; 
Mexico,  at  Durango,  etc.;  Mariposa  and  Shasta  Co.,  Cal.; 
Sheba  and  De  Soto  mines,  Humboldt  Co.  and  near  Austin, 
JSTev.;  Heintzelman  mine,  Santa  Rita  mine,  etc.,  Arizona; 
Socorro  Co.,  New  Mexico;  Gilpin  and  Clear  Summit, 
Hinsdale  and  San  Juan  Cos.,  Col.,  a  common  silver  ore; 
Idaho;  Utah;  N.  of  Little  Rock,  Kellogg  mines,  Ark. 

Frigidite  is  a  niclceliferous  variety  from  the  Apuan  Alps. 

Chimatite.  Foliated  massive;  lead-gray;  contains  60  p.  c.  of  bis- 
muth. Peru. 

Wittichenite  (Cupreous  Bismuth).  Orthorhombic,  massive  ;  steel- 
gray;  contains  40  to  50  p.  c.  of  bismuth,  and  30  to  35  of  copper. 

OXIDES.    CHLOKIDES. 
Atacamite.— Copper  Oxichloride. 

Orthorhombic;  in  rhombic  prisms  and  other  forms;  also 
granular  massive.  Color  green  to  blackish  green.  Lustre 
adamantine  to  vitreous.  Streak  apple-green.  Translucent 
to  subtranslucent.  H.  =  3-35.  G.  =  3 -76-3 -9.  Com- 
position, CuCla  +  3Cu02H2  =  Chlorine  16-64,  oxygen  11-25, 
copper  11-25,  water  12-66  =  100.  From  the  Atacama 


COPPER. 


151 


desert,  between  Chili  and  Peru,  and  elsewhere  in  Chili; 
Bolivia;  Vesuvius;  Saxony;  Spain;  Cornwall;  N.  S.  Wales. 

Cuprite. — Red  Copper  Ore. 

Isometric.  In  regular  octahedrons,  and  modified  forms 
of  the  same.  Cleavage  octahedral.  Also  massive,  and 
sometimes  earthy.  Color  deep  red,  of  various  shades. 


Streak  brownish  red.  Lustre  adamantine  or  submetallic; 
also  earthy  (tile  ore).  Subtransparent  to  nearly  opaque. 
Brittle.  H.  =  3'5-4.  G.  =  5-99;  5-85-6-15. 

Composition.  Cu20  =  Oxygen  11*2,  copper  88 -8.  B.B. 
on  charcoal,  a  globule  of  copper.  Dissolves  in  nitric  acid. 

Diff.  Differs  from  cinnabar  in  not  being  volatile  B.B.; 
from  hematite  in  yielding  a  bead  of  copper  on  charcoal, 
and  in  copper  reactions. 

Obs..  Occurs  with  other  copper  ores  in  the  Banat,  Thu- 
ringia,  Cornwall,  at  Chessy  near  Lyons,  in  Siberia,  and 
Brazil.'  The  octahedrons  are  often  green,  from  a  coating 
of  malachite.  In  the  U.  States,  occasionally  crystallized 
and  massive  at  Schuyler's,  Somerville,  and  the  Flemington 
copper  mines,  N.  J. ;  near  New  Brunswick,  N.  J. ;  at  Bris- 
tol, Ct.;  near  Ladenton,  Rockland  Co.,  N.  Y. ;  in  the  Lake 
Superior  region;  in  Arizona;  N.  Mexico;  Utah;  Wyoming. 

Melaconite,  or  Black  Copper.  Oxide  of  copper,  CuO;  a  black  pow- 
der, and  in  dull  black  masses  and  botryoidal  concretions,  along  with 
other  copper  ores.  Abundant  in  some  of  the  copper  mines  of  the  Mis- 
sissippi Valley,  and  yields  60  to  70  per  cent,  of  copper.  Results  from 
the  decomposition  of  the  sulphides  and  other  ores.  At  the  Hiwassee 
Mine,  Polk  Co.,  Tennessee,  it  has  been  abundant.  Formerly  found 
of  excellent  quality  in  the  Lake  Superior  copper  re  don. 

Tenortte.  A  like  oxide,  occurring  in  black  flexible,  metallic  scales 
on  lavas.  Vesuvius.  Atelite  is  an  oxichloride  pseudornorph  after 
tenorite. 

Eriochalcite.     A  copper  chloride.    Vesuvius. 

Melanothallite.     Copper  chloride.    Vesuvius,  eruption  of  1870. 


152  DESCRIPTIONS   OP  MINERALS. 

SULPHATES.    TUNGSTATES. 
Ohalcanthite.— Blue  Vitriol.     Sulphate  of  Copper. 

Triclinic.  In  oblique  rhomboidal  prisms.  Also  as  an 
efflorescence  or  incrustation,  and  stalactitic. 

Color  deep  sky-blue.  Streak  uncolored.  Subtransparent 
to  translucent.  Lustre  vitreous.  Soluble,  taste  nauseous 
and  metallic.  H.  =  2-2-5.  G.  =  2-21. 

Composition.  CuOJS  -f  5  aq  (or  CuO  +  S03  +  5  aq)  = 
Sulphuric  acid  (or  sulphur  trioxide)  32*1,  copper  oxide  31  '8, 
water  36-1.  A  polished  plate  of  iron  in  solutions  becomes 
covered  with  copper. 

Obs.  Occurs  with  the  sulphides  of  copper  as  a  result  of 
their  decomposition,  and  is  often  in  solution  in  the  waters 
flowing  from  copper  mines.  In  the  Hartz ;  at  Fahlun  in 
Sweden ;  Rio  Tinto  mine,  Spain ;  Copiapo,  Chili ;  Hi- 
wassee  copper  mine,  Tenn. ;  Canton  mine,  Ga. ;  in  Arizona. 

Blue  vitriol  is  much  used  in  dyeing,  and  in  the  printing 
of  cotton  and  linen  ;  also  for  various  other  purposes  in  the 
arts.  It  has  been  employed  to  prevent  dry  rot,  by  steeping 
wood  in  its  solution ;  and  it  is  a  powerful  preservative  of 
animal  substances,  they  remaining  unaltered  when  imbued 
with  it  and  dried.  Afforded  by  the  decomposition  of  chal- 
copyrite  in  the  same  manner  as  green  vitriol  from  pyrite ; 
but  it  is  manufactured  for  the  arts  chiefly  from  old  sheath- 
ing-copper,  copper  turnings,  and  copper  refinery  scales. 

In  Frederick  Co.,  Md.,  blue  vitriol  is  made  from  a  black 
earth  which  is  an  impure  oxide  of  copper  with  copper  pyrites. 

In  some  mines,  the  solution  of  sulphate  of  copper  is  so 
abundant  as  to  afford  considerable  copper,  which  is  obtained 
by  immersing  clean  iron  in  it,  and  is  called  copper  of  cemen- 
tation. At  the  copper  springs  of  Wicklow,  Ireland,  about 
500  tons  of  iron  were  laid  at  one  time  in  the  pits  ;  in  about 
12  months  the  bars  were  dissolved,  and  every  ton  of  iron 
yielded  a  ton  and  a  half,  and  sometimes  nearly  two  tons,  of 
a  precipitated  reddish  mud,  each  ton  of  which  produced  16 
cwt.  of  pure  copper.  The  Rio  Tinto  Mine  in  Spain  is 
another  where  the  sulphate  in  solution  is  thus  utilized;  the 
waters  yield  annually  1880  cwt.  of  copper,  and  consume 
2400  cwt.  of  iron. 

Anhydrous  Copper  Sulphates. — Dokrophaniie.  Monoclinic  ;  brown ; 
Cu8O»S.  Vesuvius. 


COPPER.  153 

Hydrocyanite.  Orthorkombic  ;  green,  brownish,  sky-blue  ;  soluble. 
Vesuvius. 

Hydrous  Copper  Sulphates.— Brochantite.  Orthorhombic,  tabular ; 
color  emerald-green;  G.  =  3'8-3'9.  Urals;  Cornwall;  Mexico;  Chili; 
Australia.  Kiisumgite  and  Konigite  are  the  same. 

Langite.  Orthorhombic;  fine  blue,  greenish;  G.  =  3 '48-3 '5;  Corn- 
wall. 

Cyanotrkhite  (Velvet  Ore).  Velvet  like ;  smalt-blue  to  sky-blue. 
Moldawa. 

Arnimite.  Monoclinic;  green  ;  Planitz,  Bohemia.  Herrengrundite 
(Urvolgyite)  is  a  similar  copper  sulphate,  but  contains  some  lime; 
emerald-green.  Hungary. 

Hydrous  Copper  sodium  Sulphate. — Kronkite.    Azure-blue.    Bolivia. 

Hydrous  Copper-iron  Sulphate. — Philippite.  Azure-blue  ;  astrin- 
gent. Chili. 

Anhydrous  Copper-zinc  Sulphate  (?). — Serpierite.  Orlhorhombic, 
greenish,  bluish.  Laurium,  Greece. 

Sulphato-chloride.—Connellite.     Hexagonal ;  fine  blue.     Cornwall. 

Copper -potassium  sulphato-chloride. — Chlorothionite.  Bright  blue  ; 
soluble.  Vesuvius. 

Copper  Tungstates.—Cuprotungstite.  In  yellowish-green  crusts. 
Santiago,  Chili. 

PHOSPHATES,  ARSENATES,  VANADATES,  NITRATE. 
Olivenite. — Hydrous  Copper  Arsenate. 

Orthorhombic;  I/\I  =92°  30'.  In  prismatic  crystals; 
also  fibrous,  and  granular  massive.  Olive-green,  and  of 
other  greenish  shades,  to  liver  and  wood-brown.  Streak 
olive-green  to  brown.  Subtransparent  to  opaque.  Brittle. 
H.  =3.  G.  =  4-13-4-38;  fibrous,  3 -9-4. 

Composition.  Cu409As2  (or  4CuO  -f-  As205)  =  Arsenic 
pentoxide  40'66,  copper  oxide  56*15,  water  3*19  =  100. 
Fuses  very  easily,  coloring  the  flame  bluish  green.  B.B. 
fuses  with  deflagration,  giving  off  arsenical  fumes,  and 
affords  a  brittle  globule,  which  with  soda  yields  metallic 
copper. 

Ubs.  From  Cornwall,  the  Tyrol,  Siberia,  Chili;  Tintic 
Disk,  Utah. 

There  are  also  the  following  salts  of  copper : 

Copper  Arsenates.—Euchroite  is  bright  emerald-green  ;  contains  33 
per  cent,  of  arsenic  acid,  and  48  of  copper  oxide  ;  occurs  in  modified 
rhombic  prisms  ;  H.  =  3'75  ;  G.  =  3*39  ;  from  Libethen,  in  Hungary. 
Clinodasite  (Aphancsite)  is  of  a  dark  verdigris  green  inclining  to  blue, 
and  also  dark  blue:  H.  =  2'5-3;  G.  =  4-19-4'36;  contains  62'7  per 
cent,  of  copper  oxide  ;  from  Cornwall.  Erinite  occurs  in  emerald- 
green  mamniillatccl  coatings  ;  H.  =  4 '5-5  ;  G.  =  4'04  ;  contains  59 '4 
per  cent,  of  copper  oxide  ;  from  Limerick,  Ireland.  Liroconite  varies 


154  DESCRIPTIOXS   OF   MINERALS. 

from  sky-blue  to  verdigris-green ;  occurs  in  rhombic  prisms,  some- 
times an  inch  broad ;  H.  =  2-2 "5  ;  G.  =  2 '88-2  98.  Chalccphyllite 
(Copper  mica)  is  remarkable  for  its  thin  foliated  or  mica-like  structure; 
color  emerald  or  grass  green  ;  H.  =  2 ;  G.  =  2'43-2'66  ;  contains  58 
per  cent,  of  copper  oxide  ;  from  Cornwall  and  Hungary.  Tyrolite 
(Copper  froth)  is  another  arsenate  of  a  pale  apple-green  and  verdigris- 
green  color,  having  a  perfect  cleavage  ;  contains  43 '9  per  cent,  of 
copper  oxide  ;  from  Hungary,  Siberia,  the  Tyrol,  and  Derbyshire. 
Conichalcite,  Cornwallite,  Chlorotile,  Chenemxite,  are  names  of  other 
copper  arsenates.  These  diiferent  arsenatcs  of  copper  give  an  allia- 
ceous odor  when  heated  on  charcoal  before  the  blowpipe. 

Mixite.  A  hydrous  arsenate  containing  13  per  cent,  of  oxide  of  bis- 
muth (Bi2O3),  emerald  to  bluish  green  ;  prismatic.  Joachimstahl. 

Leucochalcite.  A  white,  silky,  hydrous  copper  arsenute.  Spessart, 
Germany. 

Trippkeite.  Tetragonal ;  bluish  green ;  copper  arsenite.  Copiapo, 
Chili. 

Chalcomenite.  A  hydrous  copper  selenite,  in  bright  blue  crystals. 
Mendoza,  S.  A. 

Copper  PJwsphates. — Pseudomalachite  (Phosphochaldte,  Ehlite,  Di- 
hydrite)  In  very  oblique  crystals,  or  massive  and  incrusting  ;  of  an 
emerald  or  blackish  green  color ;  H.  —  4*5-5  ;  G.  =  4-4'4  ;  contains 
64  to  70  per  cent,  of  copper  oxide  ;  from  near  Bonn,  on  the  Rhine,  and 
also  from  Hungary.  Libethenite  has  a  dark  or  olive-green  color,  and 
occurs  in  crystals,  usually  octahedral  in  aspect,  and  massive ;  H.  = 
4 ;  G.  =  3'6-3'8  ;  contains  86*5  per  cent,  of  oxide  of  copper ;  from 
Hungary  and  Cornwall.  Other  copper  phosphates  are  Veszelyite 
(hydrous  arseno- phosphate),  TagUite,  Isoclasite.  Torbernite  is  a  copper- 
uranium  phosphate  (p.  170).  These  phosphates  give  no  fumes  before 
the  blowpipe,  and  react  for  phosphoric  acid. 

Copper  Vanadates, —  Volborthiteis  a  copper-barium-calcium  vanadate 
from  the  Urals;  Mottrammite  and  Psittacimte,  copper  lead  vanadates, 
the  former  from  England,  the  latter  from  gold-mines  in  Silver  Star 
district,  Montana. 

Thrombolite,  an  antimonate.     Stetefeldite,  Partzite,  antimonite. 

Eiwtite.    Yellowish-green  copper  antimonate  and  carbonate. 

Gerhardtite.  Copper  nitrate  in  orthorhombic  crystals  ;  dark  green; 
insoluble.  United  Verde  Mines,  Jerome,  Ariz. 

CARBONATES. 
Malachite.— Green  Copper  Carbonate. 

Monoclinic.  Usual  in  incrustations,  with  a  smooth  tube- 
rose, botryoidal,  or  stalactitic  surface  ;  structure  finely  and 
firmly  fibrous.  Also  earthy. 

Color  light  green,  streak  paler.  Usually  nearly  opaque  ; 
crystals  translucent.  Lustre  of  crystals  adamantine  inclin- 
ing to  vitreous  ;  but  fibrous  incrustations  silky  on  a  cross 
fracture.  Earthy  varieties  dull.  H.  =  3  -5-4.  G.  =  3  -7-4. 

Composition.     Cua04C  +  H,0  (or  2CuO  +  CO,  +  HaO) 


COPPER.  155 

=  Carbon  dioxide  (or  carbonic  acid)  19*9,  copper  oxide 
71*9,  water  8*2  =  100.  Dissolves  with  effervescence  in 
nitric  acid. 

B.B.  decrepitates  and  blackens,  colors  the  flame  green, 
and  becomes  partly  a  black  scoria.  With  borax,  fuses  to  a 
deep-green  globule,  and  ultimately  affords  a  bead  of  copper. 

Lfiff.  Readily  distinguished  by  its  copper-green  color  and 
its  associations  with  copper  ores.  Resembles  a  siliceous 
ore  of  copper,  chrysocolla,  a  common  ore  in  the  mines  of 
the  Mississippi  Valley  ;  but  it  is  distinguished  by  its  com- 
plete solution  and  effervescence  in  nitric  acid.  The  color 
also  is  not  the  bluish  green  of  chrysocolla. 

Obs.  Usually  accompanies  other  ores  of  copper,  and 
forms  incrustations,  which,  when  thick,  have  the  colors 
banded  and  delicate  in  their  shades  and  blending.  Perfect 
crystals  are  quite  rare.  The  mines  of  Siberia,  at  Nischne 
Tagilsk,  have  afforded  great  quantities  of  this  ore.  A  mass, 
partly  disclosed,  measured  at  top  9  feet  by  18 ;  and  the 
portion  uncovered  contained  at  least  half  a  million  pounds 
of  pure  malachite.  Other  noted  foreign  localities  are 
Chessy,  in  France ;  Santilodge,  in  Shetland ;  Schwatz  in 
the  Tyrol ;  Cornwall ;  the  Island  of  Cuba ;  Serro  do  Bembe, 
west  coast  of  Africa ;  copper  mines  of  Australia  ;  Chili. 

Occurs  in  Cheshire,  Ct. ;  Morgantown,  Perkiomen,  and 
Phcenixville,  Pa. ;  SchuylePs  Mine,  and  the  New  Brunswick 
copper  mine,*S\  J. ;  between  Newmarket  and  Taneytown 
in  the  Catoctin  Mountains,  Md.;  in  the  Blue  Ridge,  Pa., 
near  Nicholson's  Gap ;  also  in  Tintic  district,  Utah  ;  Cal- 
averas  Co.,  Cal. ;  Colorado;  Arizona;  Idaho.  At  Mineral 
Point,  Wisconsin,  a  bluish  silico-carbonate  of  copper  occurs, 
which  is  foFffie  most  part  chrysocolla,  or  a  mixture  of  this 
mineral  with  the  carbonate. 

Receives  a  high  polish  and  is  used  for  tables,  mantel- 
pieces, vases;  and  also  ear-rings,  snuff-boxes,  and  various 
ornamental  articles.  Too  soft  to  be  much  prized  in  jewelry. 
The  tables,  vases,  and  other  articles  made  of  it  have  great 
beauty. 

Malachite  is  sometimes  passed  off  in  jewelry  as  turquois, 
though  easily  distinguished  by  its  shade  of  color  and  much 
inferior  hardness.  It  is  a  valuable  ore  when  abundant;  but 
it  is  seldom  smelted  alone,  because  the  metal  is  liable  to  es- 
cape with  the  liberated  volatile  ingredient. 


156  DESCRIPTIONS   OF   MINERALS. 

fl          Azurite. — Blue  Copper  Carbonate.    Blue  Malachite. 

Monoclinic.  In  modified  oblique  rhombic  prisms,  the 
crystals  rather  short  and  stout; 
lateral  cleavage  perfect.  Also 
massive.  Often  earthy. 

Color  deep  blue,  azure-blue, 
Berlin-blue.  Transparent  to  nearly 
opaque.  Streak  bluish.  Lustre 
vitreous,  almost  adamantine. 
Brittle.  H.  =  3-5-4-5.  G.  = 
3  -5-3  -83. 

Composition.      Cu307Ca  +  H20 

(or  30uO  +  2C02  +  H20)  =  Carbon  dioxide  25 -6,  copper 
oxide  69*2,  water  5*2.  B.B.  and  in  acids  like  the  preced- 
ing. 

Obs.  Accompanies  other  ores  of  copper.  Chessy,  France, 
has  afforded  fine  crystals;  found  also  in  Siberia;  the  Banat; 
near  Redruth  in  Cornwall;  at  Phoenixville,  Pa.,  in  crystals; 
in  Wisconsin  near  Mineral  Point;  as  incrustations,  and 
rarely  as  crystals,  near  New  Brunswick,  !N".  J. ;  near  Nichol- 
son's Gap,  in  the  Blue  Ridge,  Pa. 

When  abundant,  a  valuable  ore  of  copper.  Makes  a  poor 
pigment,  as  it  is  liable  to  turn  green. 

AuricTialdte  (Buratite).  A  hydrous  copper-zinc  carbonate,  or  a 
cuprous  hydrozincite  ;  pale  green  to  sky-blue ;  Altai ;  Eetzbanya ; 
Chessy  in 'France;  Tyrol;  pain;  Leadhills  in  Scotland;  Lancaster, 
Pa. 

SILICATES. 
Dioptase. — Copper  Silicate. 

Rhombohedral;  7?  A  #  =  126°  24'.  Occurs  in  six-sided 
prisms  with  rhombohedral  terminations.  Color  emerald- 
green.  Lustre  vitreous.  Transparent  to  nearly  opaque. 
H.  =  5.  G.  =3-28-3-35. 

Composition.  CuH,04Si  =  Silica  38*1,  copper  oxide  50 '4, 
water  11*5  =  100.  B.B.  with  soda  on  charcoal  yields  copper, 
and  this,  with  its  hardness,  distinguishes  it  from  the  spe- 
cies it  resembles. 

Obs.  From  the  Khirgeez  Steppes  of  Siberia;  Chili;  near 
Clifton,  Arizona. 


COPPER.  157 

Chrysocolla.— Hydrous  Copper  Silicate. 

Usually  as  incrustations;  botryoidal  and  massive;  in  thin 
seams  and  stains;  no  fibrous  or  granular  structure  apparent, 
nor  any  appearance  of  crystallization. 

Color  clear  bluish  green.  Lustre  of  surface  of  incrusta- 
tions smoothly  shining;  also  earthy.  Translucent  to  opaque. 
H.  =  2-4.  G.  =  2-24. 

Composition.  CuO,Si  +  2aq  (or  CuO-|-Si02  +  2aq)  = 
Silica  34*2,  copper  oxide  45*3,  water  20-5  =  100. 

SIBERIAN.  NEW  JERSEY. 

Von  Kobell.  Berthier          Bo  wen.          Beck. 


Oxide  of  copper. . .  40'0     551 

Silica 36-5     35'4 

Water 20-2 28'5 

Carbonic  acid 2*1  

Oxide  of  iron. ..          1-0  .                   .  — 


45-2 
37-3 
17-0 


42-6 
40-0 
160 

1-4 


Varies  much  in  the  proportion  of  its  constituents,  as  it  is 
not  crystallized.  Pilarite  is  an  aluminous  variety. 

B.B.  blackens  in  the  inner  flame,  and  yields  water 
without  melting.  With  soda  on  charcoal  yields  a  globule 
of  copper. 

Diff.  Distinguished  from  green  malachite  as  stated  under 
that  species. 

Obs.  Accompanies  other  copper  ores  in  Cornwall,  Hun- 
gary, the  Tyrol,  Siberia,  Thuringia,  etc.  Abundant  in 
Chili  at  various  mines ;  in  Wisconsin  and  Missouri  worked 
for  copper.  Formerly  taken  for  green  malachite.  Occurs 
at  the  Somerville  -and  Schuyler's  mines,  ISL  J.;  at  Mor- 
gantown,  Pa.;  Cheshire,  Ct.;  Utah,  Colorado ";"  California; 
N.  S.  Wales. 

This  ore  in  the  pure  state  affords  30  per  cent,  of  copper; 
but  as  it  occurs  in  the  rock  will  hardly  yield  one-third  this 
amount.  Still,  when  abundant,  as  it  appears  to  be  in  the 
Mississippi  Valley,  it  is  a  valuable  ore. 

Neocianite  is  a  blue  monoclinic  mineral,  supposed  to  be  an  anhy- 
drous copper  silicate.  Vesuvius. 

General  Remarks. — The  most  valuable  sources  of  copper  for  the  arts 
are  native  copper,  chalcopyrtte  or  "  yellow  copper  ore,"  chalcocite  or 
"copper  glance,"  bornite  or  "variegated  copper  ore,"  malachite  or 
"  green  carbonate  of  copper,"  chrysocolla  or  '  •  silicate,"  cuprite  or  "  red 
oxide  of  copper;"  and  occasionally  "  black  copper." 

The  principal  copper  regions,  exclusive  of  the  American,  are  as  fol- 
lows- The  Cornwall  and  Devon,  England,  where  the  ore  is  mostly 


158  DESCRIPTIONS   OF   MINERALS. 

chalcopyrite;  about  Mansfeld,  in  Prussia,  Laving  the  ore  distributed 
through  a  bed  of  red  shale  in  the  Permian  (Kupferschiefer),  about 
eighteen  inches  thick,  making  about  2£  per  cent,  of  the  bed;  the  Urals 
on  their  western  slope,  in  the  Permian,  as  in  Mansfeld;  also  more  pro- 
ductively on  the  eastern  side  of  the  Urals,  at  the  Nischne  Tagilsk  and 
Bogoslowskoi  mines,  in  Silurian  limestone  where  traversed  by  eruptive 
rocks,  and  at  the  Gumeschewskpi  mine,  in  argillaceous  shale,  the  ore 
chiefly  malachite  and  cuprite;  in  France,  at  Chessy,  near  Lyons,  of 
malachite  and  azurite,  now  of  little  value;  in  Norway,  at  Alten,  and 
in  Sweden,  at  Fahlun;  in  Hungary,  at  Schemnitz,  Kremnitz,  Kapnik, 
and  theJBanat;  in  Italy,  at  Monte  Catini;  in  Spain,  in  the  province  of 
Huelva,  where  is  the  Rio  Tinto  mine,  which  affords  chalcopyrite,  and 
also  the  sulphate  (p.  152);  in  Portugal,  at  San  Domingo,  near  the 
mouth  of  the  Guadiana;  in  Algeria,  Turkey,  China,  Japan,  Cape  of 
Good  Hope;  in  South  Australia,  where  arc  three  prominent  mines, 
the  Burra,  Wallaroo,  and  Moonta,  their  yield  in  1875,  £451,500;  New 
South  Wales,  the  largest  mine  at  Cobar,  500  m.  W.  of  Sydney. 

In  South  America,  in  Chili,  in  the  vicinity  of  Copiapo,  and  less 
abundantly  at  other  places  to  the  south;  in  Bolivia,  also  in  Peru,  and 
the  Argentine  Republic,  but  not  much  developed.  In  Cuba,  but  much 
less  productive  than  formerly. 

In  Eastern  North  America  some  copper  has  been  afforded  by  the 
Triassic  of  New  Jersey  and  the  Connecticut  Valley,  but  there  are  no 
producing  mines.  At  Ely,  Vt.-and  Milan,  N.  H.,  veins  of  chalcopy- 
rite are  worked.  The  chief  sources  of  copper  are  the  veins  of  Northern 
Michigan,  whore  the  veins  are  connected  with  trap-dikes  intersecting 
a  ^Cambrian  red  sandstone,  as  stated  on  page  145.  The  Cliff  mine  was 
one  of  the  earliest  opened,  and  there  the  largest  masses  of  native  copper 
have  been  found. .  Other  veins  have  since  been  opened  in  various  parts 
of  the  region,  at  Eagle  Harbor,  Eagle  River,  Grand  Marais,  Lac  La 
Belle,  Agate  Harbor,  Torch  Lake,  on  the  Ontonagon,  in  the  Porcupine 
Mountains,  and  elsewhere.  In  Tennessee,  at  the  Hiwassee  mines,  but 
work  suspended;  in  Virginia,  at  Tolersville;  in  North  Carolina,  at  Ore 
Knob;  in  Georgia,  the  Tallapoosa  mines;  in  Missouri,  in  Sainte  Gcne- 
vieveCo.,  from  one  or  two  levels  in  the  Lower  Silurian  limestone;  also 
north  of  Lakes  Superior  and  Huron,  and  on  Isle  Royale  and  the  Michi- 
picoten  Islands,  in  Lake  Superior,  but  not  now  productive;  in  New- 
foundland valuable  mines  at  Tilt  Cove  and  BettsCove  mines,  and  in 
the  vicinity  of  Capelton. 

In  Western  North  America,  in  Arizona,  there  are  large  veins  of 
copper  north  of  the  Gila,  on  the  bprders.of  New  Mexico,  in  the  Clif- 
ton, Warren,  and  Globe  districts;  in  New  Mexico,  in  the  Nacimicnto 
Mts.,  the  Sandia  Mts.,  east  of  Albuquerque,  the  Andreas  Mts.,  and 
elsewhere;  in  Colorado,  at  the  towns  of  Central,  Black  Hawk,  and 
Nevada  in  Gilpin  Co.;  in  the  San  Juan  Mts.,  north  of  Canon  City;  in 
Utah,  in  the  Tintic  district;  in  Montana,  near  Butte  City;  also  in  Idaho, 
Wyoming,  and  Nevada,  but  mostly  awaiting  development;  in  Cali- 
fornia, at  Copperopolis  (formerly  worked);  at  Spenceville  in  Nevada 
Co. 

The  total  production  of  copper  in  the  United  States  in  1845  was  100 
long  tons,  12  of  it  from  the  Lake  Superior  region;  in  1855,  3000,  with 
2693  from  L.  S.;  in  1865,  8500,  with  6410  from  L.  S.;  in  1875,  18,000, 


COPPER.  159 

with  16,089  from  L.  S.;  in  1880,  27,000,  with  22,204  from  L.  S.;  in 
1885,  74,000,  with  32,210  from  L.  S.,  30,270  from  Montana,  10,135 
from  Arizona  and  1435  from  other  States.  Tbe  world's  production 
for  1880  is  estimated  at  153,057  tons,  and  for  1885  at  221,715  tons.  Of 
the  latter,  Chili  produced  38,500  tons;  Spain  and  Portugal  about 
46,000;  Germany  about  15,000;  Australia,  11,400;  Japan,  10,000; 
Southern  Africa,  5450;  Sweden,  5000;  Venezuela,  4111;  England 
about  3000,  and  other  countries  about  9000  tons. 

In  1884,  the  Calumet  and  Hecla  mine,  Michigan,  yielded  40,473,585 
pounds;  the  Quincy,  5,680,087;  the  Osceola,  4,247,630;  the  Franklin, 
3,748,652;  the  Atlantic,  3,163,585;  all  the  other  L.  Superior  mines 
about  12,000,000  pounds. 

The  metal  copper  was  known  in  the  earliest  periods  and  was  used 
mostly  alloyed  with  tin,  forming  bronze.  The  mines  of  Nubia  and 
Ethiopia  are  believed  to  have  produced  a  great  part  of  the  copper  of 
the  early  Egyptians.  Eubo?a  and  Cyprus  are  also  mentioned  as  afford- 
ing this  metal  to  the  Greeks.  It  was  employed  for  cutting  instru- 
ments and  weapons,  as  well  as  for  utensils;  and  bronze  chisels  are  at 
this  day  found  at  the  Egyptian  stone  quarries,  that  were  once  em- 
ployed in  quarrying.  This  bronze  (chalkos  of  the  Greeks,  and  CBS  of 
the  Romans)  consisted  of  about  5  parts  of  copper  to  1  of  tin,  a  propor- 
tion which  produces  an  alloy  of  maximum  hardness.  Nearly  the 
same  material  was  used  in  early  times  over  Europe;  and  weapons  and 
tools  have  been  found  consisting  of  copper,  edged  with  iron,  indicating 
the  scarcity  of  the  latter  metal.  Similar  weapons  have  also  been 
found  in  Britain;  yet  it  is  certain  that  iron  and  steel  were  well  known 
to  the  Romans  and  later  Greeks,  and  to  some  extent  used  for  warlike 
weapons  and  cutlery.  Bronze  is  hardened  by  hammering  or  pres- 
sure. 

Copper  knives,  axes,  chisels,  spear  heads,  bracelets,  etc.,  have  been 
found  in  the  Indian  mounds  of  Wisconsin,  Illinois,  and  the  neighbor- 
ing States;  and  there  is  evidence  that  the  Indians,  besides  using  drift 
masses  of  copper,  knew  of  the  copper  veins  of  Northern  Michigan,  and 
worked  them,  especially  in  the  Ontonagon  region,  where  their  tools 
and  excavations  have  been  discovered. 

Copper  at  the  present  day  is  very  various  in  its  applications  in  the 
arts.  It  is  largely  employed  for  utensils,  for  the  sheathing  of  ships, 
and  for  coinage.  Alloyed  with  zinc  it  constitutes  brass/and  with  tin 
it  forms  bell-metal  as  well  as  bronze. 

Brass  consisTs'of  copper  65  per  cent.,  zinc  35;  with  53'5  per  cent,  of 
zinc  the  alloy  is  silver-white;  casting  brass  of  65-72  copper,  35-28  zinc; 
ormolu  or  Dutch  metal,  of  70-85  copper,  15-25  zinc,  with  0'3  of  each, 
lead  and  tin;  brass  for  latJie-work  of  60-70  copper,  28-38  zinc,  2  lead; 
Muntz  metal,  for  the  sheathing  of  ships,  60  copper,  39  zinc,  1  lead; 
spelter  solder  for  brass,  copper  50,  zinc  50. 

Bronze  for  medals  consists  of  copper  93,  tin  7;  for  speculum  metal, 
copper  60,  tin  30,  arsenic  10;  for  casting  bronze,  copper  82-83,  tin  1-3, 
zinc  17-18;  for  gun  metal,  copper  85-92,  tin  8-15;  for  bell-metal,  cop- 
per 65-80,  tin  20-35,  antimony  0-2;  antique  bronze,  copper  67-95,  tin 
8-15,  lead  0-1,  zinc  0-15. 

Lord  Rosse  used  for  the  speculum  of  his  great  ^lescope  126  parts 
of  copper  to  57£  parts  of  tin.  The  brothers  Keller,  celebrated  for 


160 


DESCRIPTIONS   OF   MINERALS. 


their  statue  castings,  used  a  metal  consisting  of  91 '4  per  cent,  of  cop- 
per, 5 '53  of  zinc,  1'7  of  tin,  and  1'37  of  lead.  An  equestrian  statue 
of  Louis  XIV.,  21  feet  high,  and  weighing  53,263  French  pounds,  was 
cast  by  them  in  1699,  at  a  single  jet. 

An  alloy  of  copper  90,  and  aluminium  10,  is  sometimes  used  in  place 
of  bronze. 

LEAD. 

Lead  occurs  rarely  native  ;  generally  in  combination  with 
sulphur ;  with  arsenic,  tellurium,  selenium,  and  in  the  con- 
dition of  sulphate,  carbonate,  phosphate  and  arsenate, 
chromate  and  molybdate. 

The  ores  of  lead  vary  in  specific  gravity  from  5  '5-8  '2. 
TJhey  are  soft,  the  hardness  of  the  species  with  metallic  lus- 
tre not  exceeding  3,  and  others  not  over  4.  They  are 
easily  fusible  before  the  blowpipe  (excepting  plumbo- 
resinite) ;  and  with  soda  on  charcoal  (and  often  alone), 
malleable  lead  may  be  obtained.  The  lead  often  passes  off 
in  yellow  fumes,  when  the  mineral  is  heated  on  charcoal 
in  the  outer  flame,  or  it  covers  the  charcoal  with  a  yellow 


coating. 


Native  Lead. 


A  rare  mineral,  occurring  in  thin  laminas  or  globules. 
G.  =  11  *35.  Said  to  have  been  seen  in  the  lava  of  Madeira ; 
at  Alston  in  Cumberland  with  galena ;  .in  the  County  of 
Kerry,  Ireland  ;  in  an  argillaceous  rock  at  Carthagena ;  at 
Camp  Creek,  Montana ;  Jay  Gould  Mine,  Idaho,  in  galena. 

SULPHIDES,  SELENIDES,  TELLUKIDES. 
Galenite. — Galena.     Lead  Sulphide. 

Isometric.  Cleavage  cubic,  eminent,  and  very  easily  ob- 
tained. Also  coarse  or  fine  granular ;  rarely  fibrous. 

1.  2.  3. 


n 


Color  and  streak  lead-gray.     Lustre  shining  metallic. 
Fragile.     H.  =  2 '5.     G.  =  7 '25-7 '35  ;  6 -93-7 '7. 

Composition.     PbS  =  Sulphur   13-4,   lead    86-6  =  10& 


LEAD.  1CI 

Often  contains  some  silver  sulphide,  and  is  then  argentifer- 
ous galena  ;  at  times  zinc  sulphide  is  present.  The  ore  of 
veins  intersecting  crystalline  metamorphic  rocks  is  most 
likely  to  be  argentiferous.  The  proportion  of  silver  varies 
greatly.  In  Europe,  when  it  contains  only  7  or  8  ounces 
to  the  ton  it  is  worked  for  the  silver.  The  galenite  of  the 
Hartz  af ords  '03  to  •  05  per  cent,  of  silver  ;  the  English  '02 
to  -03  per  cent. ;  that  of  Leadhills,  Scotland,  '03  to  -06  ; 
that  of  Pike's  Peak,  Colorado,  -05  to  -06  ;  that  of  Arkan- 
sas, -03  to  -05  ;  that  of  Middletown,  Ct.,  -15  to  -20 ;  that 
of  Roxbury,  Ct.,  1'85  ;  that  of  Monroe,  Ct.,  3'0;  while 
that  of  Missouri  afforded  Dr.  Litton  only  -0012  to  -0027 
per  cent.  A  little  antimony  or  cadmium  is  sometffiies 
present. 

B.B.  on  charcoal,  it  decrepitates  unless  heated  with  cau- 
tion, and  fuses,  giving  off  sulphur,  coats  the  coal  yellow, 
•and  finally  yields  a  globule  of  lead. 

Diff.  Resembles  some  silver  and  copper  ores  in  color, 
but  its  cubical  cleavage,  or  granular  structure  when  mas- 
sive, will  usually  distinguish  it.  Its  reactions  before  the 
blowpipe  show  it  to  be  a  lead  ore,  and  a  sulphide. 

Obs.  Occurs  in  granite,  limestone,  argillaceous  and  sand- 
stone rocks,  and  is  often  associated  with  ores'of  zinc,  silver, 
and  copper.  Quartz,  barite,  or  calcite  is  generally  the 
gangue  of  the  ore;  also  at  times  fluor  spar.  The  rich  lead- 
mines  of  Derbyshire,  and  the  northern  districts  of  England, 
occur  in  the  Subcarboniferous  limestone ;  and  the  same 
rock  contains  the  valuable  deposits  of  Bleiberg,  in  Austria, 
and  the  neighboring  deposits  of  Carinthia.  The  ore  of 
Cornwall  is  in  true  veins  intersecting  slates  and  is  argentif- 
erous. At  Freiberg  in  Saxony,  it  occupies  veins  in  gneiss; 
in  the  Upper  Hartz,  and  at  Przibram  in  Bohemia,  it 
traverses  clay  slate  of  Lower  Silurian  age;  at  Sahla,  Sweden, 
it  occurs  in  crystalline  limestone.  There  are  other  valua- 
ble beds  of  galena,  in  France  at  Poullaouen  and  Huelgoct, 
Brittany,  and  at  Villefort,  Department  of  Lozere ;  in  Spain 
in  the  granite  and  argillyte  hills  of  Linares,  in  Catalonia, 
Granada,  and  elsewhere ;  in  Savoy ;  in  Netherlands  at 
Vedrin,  not  far  from  Namur;  in  Bohemia,  southwest  of 
Prague ;  in  Joachimstahl,  where  the  ore  is  worked  princi- 
pally for  its  silver  ;  in  Siberia  in  the  Daouria  Mountains  in 
limestone,  argentiferous  and  worked  for  the  silver. 

Deposits  of  this  ore  occur  in  limestone.,  in  the  States  of 
11 


162  DESCRIPTION'S    OF    MIN-ERALS. 

Missouri,  Illinois,  Iowa,  and  Wisconsin  ;  argillaceous  iron 
ore,  pyrite,  calamine  and  smithsonite  ("  dry  bone"  of  the 
miners),  blende  ("  black-jack"),  carbonate  offTeacT or  cerus- 
site,  and  barite  or  heavy  spar,  are  the  most  common  asso- 
ciated minerals ;  and  less  abundantly  chalcopyrite  and 
malachite,  ores  of  copper  ;  also  occasionally  the  lead  ores, 
anglesite  and  pyromorphite ;  and  in  the  Mine  La  Motte 
region,  black  cobalt,  and  linnasite,  an  ore  of  nickel. 

Lead  ore  was  first  noticed  in  Missouri  in  1700  and  1701. 
In  1720  the  mines  were  rediscovered  by  Francis  Eenault 
and  M.  La  Motte  ;  and  the  La  Motte  bears  still  the  name 
of  the  latter.  Afterward  the  country  passed  into  the  hands 
of  Spaniards,  and  during  that  period,  in  1763,  a  valuable 
mine  was  opened  by  Francis  Burton,  since  called  Mine  a 
Burton. 

The  lead  region  of  Wisconsin,  according  to  Dr.  D.  D. 
Owen,  comprises  62  townships  in  Wisconsin,  8  in  Iowa,  and 
10  in  Illinois,  being  87  miles  from  east  to  west,  and  54 
miles  from  north  to  south.  The  ore,  as  in  Missouri,  is 
abundant.  The  ore,  according  to  Whitney,  occupies  cavi- 
ties or  chambers  in  the  limestone  instead  of  true  veins,  and 
in  this  respect  it  is  like  that  of  Derbyshire  and  Northern 
England. 

The  mines  of  Wisconsin  and  Illinois  are  in  Lower  Silurian 
limestone  of  the  Trenton  period,  called  the  Galena  lime- 
stone ;  those  of  Southeastern  Missouri,  situated  chiefly  in 
Franklin,  Jefferson,  Washington,  St.  Franqois,  St.  Gene- 
vieve,  and  Madison  counties,  are  in  the  "  Third  Magnesian 
limestone ;"  also  Lower  Silurian,  but  of  the  Calciferous  or 
Potsdam  period  ;  those  of  Southwestern  Missouri,  situated 
mostly  in  Newtown,  Jasper,  Lawrence,  Green,  and  Dade 
counties,  and  in  the  western  part  of  McDonald,  Barry, 
Stone,  and  Christian  counties,  are  in  the  "Keokuk  lime- 
stone." of  the  Subcarboniferous  period,  but  partly  in  Web- 
ster, Taney,  Christian,  and  Barry  counties,  in  the  Lower 
Silurian  "  magnesian  limestone ;"  those  of  Central  Mis- 
souri, situated  in  Moniteau,  Cole,  Miller,  Morgan,  and 
other  counties,  are  mostly  in  the  Lower  Silurian  "magne- 
sian  limestone,"  but  partly,  as  in  Northern  M.oniteau,  in 
the  Subcarboniferous.  The  conditions  in  which  the  ore 
occurs  in  Missouri  confirms  the  opinion  of  Prof.  Whitney, 
as  to  there  being  no  true  veins.  Mr.  Adolph  Schmidt,  in 
his  account  of  the  Missouri  lead  ores,  says  that  the  deposits 


LEAD.  163 

contain  red  clay,  broken  chert,  from  the  chert  bed,  and 
portions  of  the  limestone  beds,  along  with  the  lead ;  that 
the  barite  was  introduced  after  the  lead ;  that  some  caves 
are  filled  through  all  their  ramifications,  while  others  are 
only  partly  filled;  and  he  adds  that  the  same  solvent  waters 
that  made  the  caves  and  horizontal  fissures  or  openings 
may  have  held  the  various  minerals  in  solution.  In  Derby- 
shire, England,  the  deposits  contain  fossils  of  Permian 
rocks,  showing  that,  although  occurring  in  Subcarbonif- 
erous  limestone,  they  were  much  later  in  origin. 

In  Colorado,  at  Leadville,  there  are  very  productive 
mines,  which  yield  also  gold  and  silver;  also  at  the  mines  of 
Georgetown,  in  Clear  Creek  Co.,  and  in  the  San  Juan 
district ;  in  Montana  at  several  localities  ;  in  Idaho ;  in 
Arizona ;  in  Nevada  abundant  in  the  Eureka  district,  the 
principal  mines  of  which  are  the  Richmond  and  Eureka; 
also  in  the  Castle  Dome  and  other  districts ;  in  Utah  at 
several  mines  ;  in  California,  in  Inyo  Co. ;  in  New  Mexico, 
in  the  Magdalena  Mountains,  Socorro  Co.;  and  in  Los 
Cerillos  district,  Santa  Fe  Co. 

Galenite  also  occurs  much  less  abundantly  in  the  region 
of  Chocolate  Eiver  and  elsewhere,  Lake  Superior  copper 
region  ;  on  Thunder  Bay  and  Black  Bay  ;  at  Cave-in-Rock, 
111.,  along  with  fiuorite ;  at  Rossie,  in  St.  Lawrence  Co., 
N.  Y.,  in  gneiss,  in  a  vein  3  to  4  feet  wide  near  Wurtz- 
boro'  in  Sullivan  Co.,  a  large  vein  in  millstone  grit,  at 
Ancram,  in  Columbia  Co.,  Martin sburg,  in  Lewis  Co.,  and 
Lowville;  at  Lubec  ;  and  of  less  interest  at  Blue  Hill  Bay, 
Birmingham  and  Parsonsfield,  Me. ;  at  Eaton,  Bath,  Tarn- 
worth,  and  Haverhill,  N.  H.;  at  Thetford,  Vt.;  at  South- 
ampton, Leverett,  and  Sterling,  and  Newburyport,  Mass.; 
at  Middletown,  Ct.,  formerly  worked  as  a  silver-lead  mine; 
in  Wythe  County,  Louisa  County,  Va.,  and  elsewhere ; 
at  King's  Mine,  Davidson  Co.,  N.  C.,  where  the  lead  ap- 
pears to  be  abundant ;  at  Brown's  Creek,  and  at  Haysboro', 
near  Nashville,  Tenn.;  at  Phoenixville,  Pa.;  in  Michipi- 
coten  and  Spar  Islands,  Lake  Superior. 

The  lead  of  commerce  is  obtained  from  this  ore.  It  is 
also  employed  in  glazing  common  stoneware:  for  this  pur- 
pose it  is  ground  to  an  impalpable  powder  and  mixed  in 
water  with  clay;  into  this  liquid  the  earthen  vessel  is  dipped 
and  then  bakpd. 


1G4  DESCRIPTIONS    OF   MINERALS. 

Retzbanyite,  Cosalite.    Lead  sulpho-bismuthide;  steel-gray.     Cosala 
and  Sinai  va,  Mexico;  Retzbanya,  Hungary. 
Begeerite,  another  sulpho-bismuthide.     Baltic  Lode,  Col. 
Bjelkite.     Near  Cosalite.     Bjelka  mine,  Sweden. 

LEAD  SELENIDES  AND  TELLURIDES. 

These  various  ores  of  lead  are  distinguished  by  the  fumes  B.B.,  and 
by  yielding,  on  charcoal,  ultimately,  a  globule  of  lead. 

Clausthalite,  Lead  seienide  ;  lead -gray;  fracture  granular,  occasion- 
ally foliated;  H.  —  2 '5-3;  G.  =  7'6-8'8;  B.B.  on  charcoal  a  horse- 
radish odor  (that  of  selenium).  The  Hartz.  A  lead  and  copper  seie- 
nide (Zorgite)  has  G.  —  7-7*5.  A  lead  and  mercury  seienide  (Lelir- 
bachite)  occurs, in  foliated  grains  or  masses  of  a  lead  gray  to  bluish 
and  iron-black  color. 

Altaite,  or  Lead  telluride.  Tin  white;  cleavable;  H.  =  3-3 '5;  G.  = 
8  16.  The  Altai. 

Nagyagite,  Foliated  tellurium.  Remarkable  for  being  foliated  like 
graphite;  color  and  streak  blackish  lead  gray;  H.  =1-1'5;  G.  = 
7-085;  contains  Tellurium  32'2,  lead  54'0,  gold9'0,  with  often  silver, 
copper,  and  some  sulphur.  Transylvania. 

SULPHAKSENITES,  SULPHANTTMONITES,  AND  SULPHO-BISMUTHITES. 

These  species  include,  of  (A)  SULPHARSENTTES:  Freieslebenite  (p' 
133),  Sartorite,  Dufrenoysite,  Guitermanite;  of  (B)  SULPHANTIMO- 
NITES:  Jamesonite,  Boulangerite,  Zirikenite,  Plagionite,  Semseyite, 
Brongniardite  (p.  138),  Meneghinite,  Geocronite,  Durfeldtite,  Plumbo- 
stannite  (containing  16  p.  c.  tin);  of  (C)  SULPHO-BISMUTHITES:  Kobel- 
lite,  Aildnite,  Alaskaite,  Galenobismutite.  Of  ^hesc  only  Jamesonite, 
Boulangerite,  Zinkenite,  Aikinite,  Kobdlite  occur  often  in  fibrous 
forms. 

A.  Dufrenoysite.     Orthorhombic;  blackish  lead-gray.     Binnen. 

Jamesonite.  Orthorhombic;  usually  fibrous  (Feather  ore],  also  mas- 
sive; lead-gray;  G.  =  5'5-5'7.  Cornwall;  Hungary;  Siberia;  Tus- 
cany; Arkansas. 

Guitermanite.  Bluish  gray,  slightly  metallic;  G.  =  5'94;  about  62 
p.  c.  of  lead.  The  Zuni  mine,  San  Juan  Co.,  Col. 

B.  Boulangerite.      Plumose  and  massive;   bluish  lead-gray;  G.  = 
5'75-6.     Moliercs,  France;  Wolfsberg,  Hartz;  Tuscany. 

Zinkenite.  Orthorhombic:  rolor  and  streak  steel-gray;  G.  =  5'30- 
to  5'35.  Wolfsberg,  Hartz;  Brobdignag  mine,  San  Juan  Co.,  Col. 

Plagionite.  Monoclinic ;  blackish  lead-gray;  G.  =  5P4.  Wolfs- 
berg. 

MenegJiinite.  Monoclinic;  G.  =  6 '4.  Bottino,  Tuscany;  Marble 
Lake,  Ontario,  Canada. 

Aildnite  (Needle  ore}.  Acicular  crystals  and  massive;  contains  cop- 
per with  the  lead.  Beresof,  Ural;  gold  region,  Georgia. 

C.  Kobellite.    Resembles   stibnite.      Contains  40  p.  c.  of  lead  and 
27  of  bismuth.      Sweden;  near  Leadviile,  on  Printerboy  Hill,  Col. 
(affording  about  44  p.  c.  of  lead  and  33  of  bismuth). 

Galenobismutite.  Contains  27  p.  c.  of  lead  to  54  of  bismuth. 
Sweden. 


LEAD.  165 

Alnskaite.  Massive,  whitish  lead-gray.  Contains  lead  and  silver, 
•with  45  to  57  p.  c.  of  bismuth.  Alaska  mine,  San  Miguel  Co.  (San 
Juan  region),  Col. 

OXIDES. 
Minium.— Oxide  of  Lead. 

Pulverulent.  Color  bright  red,  mixed  with  yellow.  Gr.  = 
4*6.  Composition,  Pb304.  B.B.  affords  globules  of  lead  in 
the  reduction  flame. 

Obs.  Occurs  at  various  mines,  usually  associated  with 
galena,  and  is  found  at  Austin's  Mines,  Wythe  Co.,  Va.; 
with  cerussite. 

Uses.  Minium  is  the  red  lead  of  commerce  ;  but  for  the 
arts  it  is  artificially  prepared. 

Plumbic  ochre.     Lead  protoxide  ;  color  yellow. 

Mendipite.  Orthorhombic ;  white,  yellowish  or  reddish;  nearly 
op  que;  pearly  ;  G.  =  7-7-1 ;  PbCl2  -h  PbO  =  Chloride  of  lead  884, 
lead\>xide61-6.  Mendip  Hills.  Matlockite  is  Pb2OCl2. 

Cotunnite.  Chloride  of  lead,  PbCl2 ;  acicular  crystals ;  white ; 
contains  74*5  per  cent,  of  lead.  Vesusius. 

Plumbogummite.  In  globular  forms  ;  yellowish  or  reddish-brown  ; 
lustre  somewhat  like  gum  arabic ;  H.  =4-45;  G.  —  6'3-6'4  ;  also 
a  variety  4-4'9  ;  consists  of  lead,  alumina,  and  water.  Huelgoet  in 
Brittany ;  lead-mine  in  Beaujeu ;  the  Missouri  mines,  with  black 
cobalt ;  Canton  mine,  Ga. 

SULPHATE,  CHROMATES,  TUNGSTATE,  MOLYBDATB. 
Anglesite.— Lead  Sulphate. 

Orthorhombic;  /A  /  =  103°  43i'. 
In  rhombic  prisms  and  other  forms. 
Lateral  cleavage.  Also  massive; 
lamellar  or  granular. 

Color  white  or  slighly  gray  or 
green.  Lustre  adamantine  ;  some- 
times a  little  resinous  or  vitreous. 
Transparent  to  nearly  opaque.  Brit- 
tle. H.  =  2-75-3.  Q.  =  6-35-6-4. 

Composition.    PbO,S  (or  PbO  + 
SO.,),  affording  about  73  per  cent, 
of  lead  oxide.     B.B.  fuses  in  the  flame  of  a  candle;  on 
charcoal,  with  soda,  yields  lead. 

Diff.  Distinguished  by  its  specific  gravity,  and  by  yield- 
ing lead.  B.B  differs  from  lead  carbonate  in  lustre,  and 
in  not  dissolving  with  effervescence  in  acid. 


166  DESCRIPTIONS   OF  MINERALS. 

Obs.  Usually  associated  with  galenite,  and  results  from 
its  decomposition.  Occurs  in  fine  crystals  at  Leadhills  and 
Wanlockhead,  Great  Britain,  and  also  at  other  foreign  lead- 
mines.  In  the  United  States,  at  the  lead-mines  of  Missouri 
and  Wisconsin ;  in  fine  crystallizations  at  Phcenixville, 
Pa.;  sparingly  at  the  Walton  gold-mine,  Louisa  Co.,  Va.; 
at  Southampton,  Mass.;  in  Arizona,  in  many  mines;  Cerro 
Gordo,  Gal.;  Clear  Creek  and  Lake  Cos.,  Col.;  Nevada; 
Utah. 

Linarite.  Hydrous  lead -copper  sulphate  ;  deep  azure-blue  ;  one 
perfect  cleavage  ;  ,  G.  =  5'3-5 '45.  Leadhills,  Red  Gill,  Keswick  ; 
Schneeberg;  Urals. 

Lead  Sulphate-carbonates,  Anhydrous.— Caledonite.  .  Color  verdi- 
gris to  bluish  green.  Leadhills,  etc. ;  Mine  la  Motte,  Mo. 

LeadMllite  (Maxite).  Orthorhombic ;  white,  yellow,  gray;  G.  = 
6 '25-6 '45.  Leadhills,  etc.  Susannite;  the  same,  but  rhombohedral. 

Lanarkite.  Monoclinic  ;  white,  yellowish,  gray,  greenish ;  G.  = 
6*3-7.  Leadhills,  Lanarkshire,  Scotland  ;  Siberia  ;  Hartz  ;  Tyrol. 

Crocoite. — Crocoisile.    Lead  Chromate. 

Monoclinic.  In  oblique  rhombic  prisms,  massive,  of  a 
bright  red  color  and  translucent.  Streak  orange-yellow. 
H.  =2-5-3.  G.  =5 -9-6-1. 

Composition.  Pb04Cr  (or  PbO  +  CrO,)  =  Chromium 
trioxide  31-1,  lead  oxide  68-9.  Blackens  and  fuses,  and 
forms  a  shining  slag  containing  globules  of  lead, 

Obs.  Occurs  in  gneiss  at  Beresof  in  Siberia,  and  also  in 
Brazil;  Vulture  region,  Arizona.  This  is  the  chrome 
yellow  of  the  painters. 

PJuBnicochroite  (or  MelanocJiroite).  Another  lead  chromate ;  con- 
tains 23 '0  of  chromium  trioxide,  and  is  dark  red  ;  streak  brick-red  ; 
crystals  usually  tabular  and  reticulately  arranged ;  G.  =  5 '75. 
Siberia;  Arizona. 

Vauquelinite.  A  lead-copper  chromate;  very  dark  green  or  pearly- 
black  ;  usual  in  minute  irregularly  aggregated  crystals ;  also  reni- 
form  and  massive;  H.  =  2'5-3  ;  G.  =  5 -5-5 '8.  Siberia;  Brazil; 
lead-mine  near  Sing  Sing,  mammillary  ;  Arizona. 

Stolzite,  or  Lead  tungstate.  In  square  octahedrons  or  prisms  ;  green, 
gray,  brown,  or  red.  Lustre  resinous  ;  H.  —  2'5-3  ;  G.  =  7'9-8'l ; 
contains  51  of  tungstic  acid  and  49  of  lead.  Zinnwald. 

Wulfemte,  or  Lead  molybdate.  In  tetragonal  crystals,  octahedral 
and  tabular ;  also  massive ;  yellow  ;  lustre  resinous ;  contains 
molybdenum  trioxide  34 '25,  lead  protoxide  64 '42.  Bleiberg  and  else- 
where in  Carinthia  ;  Hungary  ;  sparingly  at  Southampton,  Mass. ;  in 
fine  crystals  at  Phcenixville,  Pa.;  at  Tecoma  and  Eureka,  Nev.; 
Silver  and  other  districts,  Arizona  ;  in  Los  Ccrillos,  N.  Mexico. 


LEAD. 


167 


PHOSPHATES,  AESENATES,  VANADATES,  ANTIMONATES. 
Pyromorphite.— Lead  Phosphate. 

Hexagonal.  In  hexagonal  prisms;  often 
in  crusts  made  of  crystals.  Also  in  globules 
or  reniform,  with  a  radiated  structure. 

Color  bright  green  to  brown  ;  sometimes 
fine  orange-yellow,  owing  to  an  intermixture 
with  chromate  of  lead.  Streak  white  or 
nearly  so.  Lustre  more  or  less  resinous. 
Nearly  transparent  to  subtranslucent.  Brit- 
tle. H.  =  3-5-4.  G.  =  6-8-7-1 ;  impure  5-6. 

Composition.  Pb308P2  +  £PbCl2  (or  3  PbO  +  P20B  +  $ 
Pb  Cla)  =  Phosphorus  pentoxide  15-71,  lead  oxide  82 -27, 
chlorine  2  -62  =  100-60.  B.B.  fuses  easily  in  the  forceps, 
coloring  the  flame  bluish  green.  On  charcoal  fuses,  and 
on  cooling  the  globule  becomes  angular ;  coats  the  coal 
white  from  the  chloride,  and,  nearer  the  assay,  yellow  from 
lead  oxide.  Soluble  in  nitric  acid. 

Diff.  Has  some  resemblance  to  beryl  and  apatite,  but  is 
quite  different  in  its  action  before  the  blowpipe,  and  much 
higher  in  specific  gravity. 

Obs.  Leadhills,  Wanlockhead,  and  some  lead-mines  of 
Europe  are  foreign  localities.  In  the  IT.  States,  well  crys- 
tallized at  King's  Mine,  in  Davidson  Co.,  N.  C.;  other 
localities  are  the  Perkiomen  and  Phoenixville  mines,  Pa.; 
Lubec  lead-mines,  Me.;  Lenox,  N.  Y.;  formerly,  a  mile 
south  of  Sing  Sing,  N.  Y. ;  the  Southampton  lead-mine, 
Mass.;  sparingly  in  Arizona,  Mexico,  New  Mexico,  and 
Nevada,  where  the  phosphate  is  replaced  by  vanadate. 

The  name  pyromorpliite  is  from  the  Greek  pur,  fire,  and 
morphe,  form,  alluding  to  its  crystallizing  on  cooling  from 
fusion  before  the  blowpipe. 

Mimetite.  A  lead  arsenate,  resembling  pyromdrphite  in  crystalliza- 
tion, but  giving  a  garlic  odor  on  charcoal  B.B. ;  pale  yellow,  passing 
into  brown;  H.  =  2'75-3'5;  G.  =  6'41:  composition,  Pb3O8As2-}-£  Pb 
C12  =  Arsenic  pentoxide  23'20,  lead  oxide  74 '96,  chlorine  2'80  =  100-56. 
Cornwall  and  elsewhere;  Phoenixville,  Pa. ;  Vulture  distr.,  Arizona. 
EndlicMte  is  a  vanadiferous  mimetite  from  New  Mexico. 

Hedypliane  is  a  varietv  of  mimetite  containing  much  lime;  amor- 
phous; whitish;  lustre  adamantine;  H.  =  3'5-4;  G.  =  5'4-5'5.  Long- 
ban,  Sweden. 

Karyinite.  A  lead  arsenate  containing  manganese  and  calcium. 
Norway. 

Ecdemite,    Lead  chloro-arsenate;  yellow  to  green.    Sweden. 


168 


DESCRIPTIONS   OF   MINERALS. 


Achrematite.  Lead  arsenate  and  molybdate;  color  yellow  to  red.  A 
doubtful  species.  Mexico. 

Phosphochromtte.     A  chromate  and  phosphate.    Beresof . 

Vanadinile.  A  lead  vanadate.  Hexagonal;  in  prisms  like  pyro- 
morphite,  and  also  in  implanted  globules;  yellow  to  reddish  brown  and 
red;  H.  =  2*75-3;  G.  —  69-7 '23.  Zimapan,  Mexico;  in  the.  silver  dis- 
tricts of  Arizona  in  red  and  orange  crystals;  Los  Cerillos,  N.  Mexico. 
Wanlockhead  in  Dumfriesshire. 

Descloizite.  Lead  vanadate;  orthorhombic;  black,  brown,  olive- 
green.  Cordoba;  New  Mexico;  Arizona;  Carinthia. 

BraclcebuscMte.      A  hydrous  lead  vanadate.     Cordoba. 

DecJienite.     A  lead-silver  vanadate.     Dahn  and  Freiberg. 

Mollrammite.  Lead  copper  vanadate;  black.  Mottram,  St.  An- 
drews, England. 

Eusynchite.  Lead  copper  vanadate;  olive-green,  blackish.  Laurium, 
Greece. 

Lead-copper  vanadate;  green  to  olive-green.     Mon- 


Psittacinite. 
tana. 

TritocTiorite. 
Monimolite. 


Lead-copper-zinc  vanadate;  S.  America  or  Mexico. 
A  yellow  lead  aiitimonate. 
Nadorite.     A  yellow  lead  chlor-antinionate. 
Arequipite.     Lead  silico-antimonate;  wax-like  yellow. 
Coronguite.    A  doubtful  lead-silver  antimonate. 
Bindheimite.     A  hydrous  lead  antimonate. 

Lead-selenite.     Cacheuta,  S.  A. 


Peru. 


CARBONATES,  SILICATES. 
Cerussite. — White  Lead  Ore.    Lead  Carbonate . 


Orthorhombic;  /A  /=  117°  13'.  In  modified  right  rhom- 
bic prisms;  often  in  compound  crystals,  two  or  three  crosw- 


1. 


ing  one  another  as  in  Fig.  2.  Also  in  six-sided  prisms 
like  aragonite.  Also  massive;  rarely  fibrous. 

Color  white,  grayish,  light  or  dark.  Lustre  adamantine. 
Brittle.  H.  =  3-3  -5.  G.  =  6  -46-6  -48. 

Composition.  Pb03C  (or  PbO  -|-  COJ  =  Carbon  dioxide 
16*5,  lead  oxide  83 '5  =  100.  B.B.  decrepitates,  fuses,  and 
with  care  on  charcoal  affords  a  globule  of  lead.  Effervesces 
in  dilute  nitric  acid. 


LEAD.  169 

Diff.  Distinguished  by  its  specific  gravity  and  yielding 
lead  Vheii  heated.  From  anglesite  it  differs  in  giving  lead 
alone  on  charcoal  B.B.,  as  well  as  by  its  solution  and  effer- 
vescence with  nitric  acid,  and  its  less  glassy  lustre. 

Obs.  Associated  usually  with  galena.  Finely  crystallized 
at  Leadhills,  Wanlockhead,  and  Cornwall;  also  Linares, 
Spain,  and  other  lead-mines  in  Europe. 

In  the  IT.  S.,  at  Austin's  Mines,  Wythe  Co.,  Va.;  at 
King's  Mine,  in  Davidson  Co.,  N.  0.  ;  at  the  latter 
place  it  has  been  worked  for  lead,  and  it  is  associated 
with  native  silver  and  pyromorphite ;  Perkiomen  and 
Phoenixville,  Pa.;  at  "Vallee's  Diggings/'  Jefferson  Co., 
Mo.,  and  other  mines  in  that  State;  at  Brigham's  Mine,, 
near  the  Blue  Mounds,  Wis.,  partly  in  stalactites;  at  "Deep 
Diggings,"  in  crystals,  and  at  other  places,  both  massive 
and  in  fine  crystallizations;  in  Colorado  and  many  Western 
mining  regions  with  other  lead  ores. 

When  abundant,  this  ore  is  wrought  for  lead.  Large 
quantities  occur  about  the  mines  of  the  Mississippi  Valley. 
It  was  formerly  buried  up  in  the  rubbish  as  useless,  but  it 
has  since  been  collected  and  smelted.  It  is  a  rich  ore,  af- 
fording in  the  pure  state  75  per  cent,  of  lead. 

The  "white  lead"  of  commerce,  extensively  used  as  a 
paint;  but  the  material  so  used  is  artificially  made. 

Phosgenite,  or  Corneous  Lead.  A  lead  chloro-carbonate,  occurring 
in  whitish  adamantine  crystals.  H.  =  2'75-4.  G.  =  6-6'3.  Composi- 
tion, PbOsC  -f  PbCl2.  Derbyshire  and  Germany. 

Hydrocerussite.  Hydrous  lead  carbonate,  on  native  lead.  From 
Sweden. 

Ganomalite.  A  white  lead-manganese  silicate,  affording  34*89  per 
cent,  of  lead  oxide.  Sweden.  Hyalotecite  is  a  lead-barium-lime  sili- 
cate. Melanotecite  is  a  lead-iron  silicate.  Kentroliie  is  a  lead-manga- 
nese silicate;  G.  =  6 '19. 

General  Remarks. — The  lead  of  commerce  is  derived  almost  wholly 
from  the  sulphide  of  lead  or  galenite,  the  localities  of  which  have 
already  been  mentioned;  yet  in  some  mining  regions,  the  carbonate  and 
sulphate  are  also  abundant. 

The  lead-mines  of  the  Central  United  States  afforded  in  1826,  1770 
tons;  in  1842,  24,000  short  tons;  in  1872,  25,880;  1875,  60,000;  1877, 
82,000;  1880,  98,000;  1884,  140,000  short  tons. 

In  1884,  Nevada  produced  4000  tons;  Utah,  28,000;  Colorado,  63,165; 
Montana, 7000;  Idaho,  7500;  N.  Mexico,  6000;  Arizona,  2700;  California, 
1000;  the  States  on  the  Mississippi,  19,676;  Virginia,  256.  Great  Britain 
produced  in  1874  about  59,000  long  tons;  in  1883,  39,160.  In  1883, 
Germany  produced  96,400  tons;  Spain,  129,000  tons;  France,  8000 
tons;  Italy,  9000  tons;  Austria,  11,320  tons. 


170 


DESCRIPTIONS   OF   MINERALS. 


ZINC. 

Zinc  occurs  in  combination  with  sulphur  and  oxygen; 
and  also  in  the  condition  of  silicate,,  carbonate,  sulphate, 
and  arsenate.  It  is  also  a  constituent  of  one  variety  of  the 
species  spinel.  The  chief  sources  of  the  metal  are  smith- 
soniteor  the  carbonate;  willemite  and  calamine,  or  silicates; 
zincite,  or  the  oxide;  sphalerite  (blende),  or  the  sulphide; 
and  franklinite.  Native  zinc  has  been  reported  from 
Northern  Alabama. 


Sphalerite.— Blende.    Zinc  Sulphide.    Black  Jack. 

Isometric.  In  dodecahedrons,  octahedrons,  and  other 
allied  forms,  with  a  perfect  dodecahedral  cleavage.  Also 
massive;  sometimes  fibrous.  Color  wax-yellow,  brownish 
yellow  to  black,  sometimes  green,  red,  and  white;  streak 


2. 


3. 


white  to  reddish  brown.  Lustre  resinous  or  waxy,  and 
brilliant  on  a  cleavage  face;  sometimes  submetallic.  Trans- 
parent to  subtranslucent.  Brittle.  H.  =3*5-4.  G.  =3*9-4*2. 
Some  specimens  become  electric  with  friction,  and  give  off 
a  yellow  light  when  rubbed  with  a  feather. 

Composition.  ZnS  =  Sulphur  33,  zinc  67  =  100.  Con- 
tains frequently  iron  sulphide  when  dark-colored;  often 
also  1  or  2  per  cent,  of  cadmium  sulphide,  especially  the 
red  variety;  also  sometimes  indium  and  gallium.  Nearly 
infusible  alone  and  with  borax.  Dissolves  in  nitric  acid, 
emitting  sulphuretted  hydrogf  n.  Strongly  heated  on  char- 
coal yields  fumes  of  zinc. 

Diff.  This  ore  is  characterized  by  its  lustre, '  cleavage, 
and  its  being  nearly  infusible.  Some  dark  varieties  ^ook  a 
little  like  tin  ore,  but  their  cleavage  and  inferior  hardness 
distinguish  them;  and  some  clear  red  crystals,  which  resein- 


zixc.  171 

ble  garnet,  are  distinguished  by  the  same  characters  and 
also  by  their  very  difficult  fusibility. 

Obs.  Occurs  in  rocks  of  all  ages,  associated  generally 
with  ores  of  lead,  and  often  also  with  copper,  iron,  tin,  and 
silver  ores.  The  lead-mines  of  Missouri  and  Wisconsin 
afford  this  ore  abundantly.  Other  localities  are,  at  Lubec, 
Bingham,  Dexter,  Parsonsfield,  Me.;  at  Eaton,  Warren, 
Haverhill,  Shelburne,  N.  H.;  at  Hatfield,  Vt.;  in  Brook- 
field,  Berlin,  Roxbury,  and  Monroe,  Ct. ;  at  Ancram  lead- 
mine,  the  Wurtzboro'  lead  vein,  at  Lockport,  Root,  2  miles 
southeast  of  Spraker's  Basin,  in  Fowler,-  at  Clinton,  N.  Y. ; 
at  Franklin,  N.  J.,  colorless  (Cleiophane)',  at  the  Perkio- 
men  lead  mine,  Pa.;  and  a  compact  variety  abundant  at 
Friedensville,  Saucon  Valley,  Pai ;  with  calamine  in  lower 
Silurian  limestone,  at  Austin's  lead  mine,  Wythe  Co.,  Va.; 
near  PowelFs  River,  and  at  Haysboro',  Tenn. ;  at  Prince's 
Mine,  Spar  Island,  Lake  Superior,  with  ores  of  silver;  in 
Beauce  Co.,  Canada,  where  it  is  slightly  auriferous;  also  at 
various  mines  in  Colorado,  Arizona,  Utah,  Montana,  New 
Mexico,  Idaho,  California;  in  fine  crystals  at  Joplin,  Mo. 

A  useful  ore  of  zinc,  though  more  difficult  of  reduction 
than  calamine.  By  its  decomposition  (like  that  of  pyrite) 
it  affords  sulphate  of  zinc  or  white  vitriol. 

Wurtzite.  Zinc  sulphide  in  hexagonal  crystals.  From  Bolivia; 
Butte  Mine,  Montana.  Erythrozincite  is  supposed  to  be  a  manganesian 
variety  of  wurtzite. 

Huascolite  is  a  zinc-lead  sulphide.     Youngite  is  probably  a  mixture. 

Zincite.— Red  Zinc  Ore.    Zinc  Oxide. 

Hexagonal.  Usually  in  foliated  masses,  or  in  dissemi- 
nated grains;  cleavage  eminent,  nearly  like  that  of  mica; 
but  the  laminae  brittle,  and  not  so  easily  separable. 

Color  deep  or  bright  red,  by  transmitted  light  deep 
yellow;  streak  orange-yellow.  Lustre  brilliant,  subadaman- 
tine.  Translucent  or  sub  translucent.  H.  =  4-4-5.  G.  = 
5-G8-5-74. 

Composition.  ZnO  =  Oxygen  19-7,  zinc  80-3  =  100. 
B.B.  infusible  alone,  but  yields  a  yellow  transparent  glass 
with  borax;  on  charcoal,  a  coating  of  zinc  oxide.  Dissolves 
in  nitric  acid  without  effervescence. 

Diff.  Distinguished  by  its  eminent  cleavage,  inf  usibility, 
and  also  by  its  mineral  associations. 


172  DESCRIPTIONS   OF   MINERALS. 

Obs.  Occurs  with  franklinite  at  Mine  Hill  and  Sterling 
Hill,  Sussex  Co.,  N.  J. 
A  good  ore  of  zinc,  and  easily  reduced. 

Voltzite.  Sulphur,  oxygen  and  zinc,  4ZnS+ZnO;  in  implanted 
globules;  dirty  rose-red;  pearly  on  a  cleavage  surface.  France;  near 
Joachimstahl. 

HydrofmnkUnite.  Isometric  octahedrons;  iron  black;  supposed  to 
be  hydrous  oxide  of  zinc  and  iron.  Sterling  Hill,  N.  J. 

Goslarite.— Zinc  Sulphate.    White  Vitriol. 

Orthohombic;  I/\I=  90°  42'.  Cleavage  perfect  in  one 
direction. 

Color  white.  Lustre  vitreous.  Easily  soluble;  taste  as- 
tringent, metallic,  and  nauseous.  Brittle.  H.  =  2-2  "5. 
G.  =  2-036;  artificial,  1 -95-1 '96. 

Composition.  Zn04S  +  7  aq.  (or  ZnO  -f  S03  +  7  aq.)  = 
Zinc  oxide  28 '2,  sulphur  trioxide  27 '9,  water  43 -9  =  100. 
B.  B.  gives  off  fumes  of  zinc  on  charcoal,  which  cover  the 
coal. 

Obs.  Results  from  the  decomposition  of  blende.  Occurs 
in  the  Haitz;  Hungary;  Sweden;  at  Holywell  in  Wales. 

Extensively  employed  in  medicine  and  dyeing.  Prepared 
to  a  large  extent  from  blende  by  decomposition,  though 
this  affords,  owing  to  its  impurities,  an  impure  sulphate. 
Also  obtained  by  direct  combination  of  zinc  with  sulphuric 
acid. 

White  Vitriol,  as  the  term  is  used  in  the  arts,  is  one  form 
of  sulphate  of  zinc,  made  by  melting  the  crystallized  sul- 
phate, and  agitating  till  it  cools  and  presents  an  appearance 
like  loaf  sugar. 

Zinc-alumintte.  Hydrous  zinc-aluminum  sulphate;  white.  Lau- 
rium,  Greece. 

Hopeite.  In  orthorhombic  crystals;  grayish  white;  supposed  to  be 
a  hydrous  zinc-phosphate.  Altenberg  zinc  mines. 

Kottigite,  Hydrous  zinc-cobalt  arsenate;  reddish  (owing  to  pres- 
ence of  cobalt).  Schneeberg. 

Adamite.    Hydrous  ziuc-arsenate;  honey -yellow  to  violet.     Chili. 

Smiths onite. — Zinc  Carbonate, 

Bhombohedral ;  R/\R  =  107°  40'.  Cleavage  R  perfect. 
Massive  .or  incrusting;  reniform  and  stalactitic. 

Color  impure  white,  sometimes  green  or  brown;  streak 


ZINC.  173 

uncolored.  Lustre  vitreous  or  pearly.  Subtransparent  to 
translucent.  Brittle.  H,  =5.  G.  =  4 '3-4 '45. 

Composition.  Zn03C  (or  ZnO  +  C02)  =  Carbon  dioxide 
35*2,  zinc  oxide  64-8  four-fifths  of  which  is  pure  zinc)  = 
100.  Of  ten  contains  some  cadmium.  B.  B.  infusible  alone, 
but  carbonic  acid  and  oxide  of  zinc  are  finally  vaporized. 
Effervesces  in  nitric  acid.  Negatively  electric  by  friction. 

D iff.  The  effervescence  with  acids  distinguishes  this 
mineral  from  the  following  species;  and  the  hardness,  diffi- 
cult fusibility,  and  the  zinc  fumes  before  the  blowpipe,  from 
the  carbonate  of  lead  or  other  carbonates.  Besides,  the 
crystals  over  a  drusy  surface  terminate  usually  in  sharp 
three-sided  pyramids. 

Obs.  Occurs  commonly  with  galena  or  blende,  and 
usually  in  calcareous  rocks.  Found  in  Siberia,  Hungary, 
Silesia;  at  Bleiberg  in  Oarinthia;  near  Aix-la-Chapelle  in 
the  Lower  Rhine,  and  largely  in  Derbyshire  and  elsewhere 
in  England.  In  the  tj.  States,  abundant  at  Joplin 
Creek,  Mine-la- Motte,  Mo.,  and  ValleVs  Diggings;  at  lead 
"diggings"  in  Iowa  and  Wisconsin;  in  Eastern  Kansas, 
near  the  Joplin  Mines;  also  in  Claiborne  Co.,  Tenn. ; 
sparingly  at  Hamburg,  near  Franklin  Furnace,  Sussex  Co., 
N.  J. ;  Perkiomen  lead  mine,  Pa. 

Hyclrozincite  (Zinc  Bloom).  Hydrous  zinc  carbonate,  ZnO3C  -|- 
2ZnO2H,  of  a  whitish  color,  with  G.  =  3'58-3'8. 

Aurichalcite.  Hydrous  zinc-copper  carbonate;  in  drusy  incrusta- 
tions of  acicular  crystals;  pale  verdigris  green  to  sky-blue.  Siberia, 
Hungary,  England,  France,  Tyrol,  Spain;  Lancaster,  Pa. 

Buratite.    A  lime  aurichalcite. 

Willemite.-Zinc  Silicate.    Troostite. 

Rhombphedral;  R/\R  =  116°  1'.-  In  hexagonal  prisms; 
also  massive. 

Color  whitish,  greenish  yellow,  apple-green,  flesh-red, 
yellowish  brown.  Streak  uncolored.  Transparent  to 
opaque.  Brittle.  H.  =  5-5.  G.  =  3-89-4-18. 

Composition.  Zna04Si(or2ZnO+SiOa)  =  Silica  27*1,  zinc 
oxide  72'9  =  100.  B.B.  fuses  with  difficulty  to  a  white 
enamel;  on  charcoal,  and  most  easily  on  adding  soda,  yields 
a  coating  which  is  yellow  while  hot,  and  white  on  cooling, 
and  which,  moistened  with  cobalt  solution  and  treated  in 
O.F.,  is  colored  bright  green.  Gelatinizes  with  hydro- 
chloric acid. 


174  DESCRIPTIONS   OF   MINERALS. 

Obs.  From  Moresnet,  between  Liege  and  Aix-la-Cha- 
pelle;  Raibel  in  Carinthia ;  Greenland.  Abundant  at 
Franklin  and  Sterling,  Sussex  Co.,  N.  J.,  mixed  with 
zincite,  and  used  as  an  ore  of  zinc;  also  in  prismatic 
crystals  that  occasionally  are  six  inches  long. 

Calamine. — Hydrous  Zinc  Silicate.     Galmei. 

Orthorhombic;  /A  7=104°  13'.  In  rhombic  prisms, 
the  opposite  extremities  with  unlike  planes.  Cleavage  per- 
fect parallel  to  /.  Also  massive  and  incrusting,  mammil- 
lated  or  stalactitic. 

Color  whitish  or  white,  sometimes  bluish,  greenish,  or 
brownish.  Streak  uncolored.  Transparent  to  translucent. 
Lustre  vitreous  or  subpearly.  Brittle.  H.  =  4*5-5.  G.  = 
316-3-9;  3-43-3-49.  Altenberg.  Pyro-electric. 

Composition.  H2Zn206Si  =  Silica  25  0,  zinc  oxide  67 '5, 
water  7'5  =  100. 

B.B.  alone  almost  infusible.  Forms  a  clear  glass  with 
borax.  Dissolves  in  heated  sulphuric  acid ;  the  solution 
gelatinizes  on  cooling. 

Diff.  Differs  from  calcite  and  aragonite  by  its  action 
with  acids;  from  a  salt  of  lead,  or  any  zeolite,  by  its  infusi- 
bility;  from  chalcedony  by  its  inferior  hardness,  and  its 
gelatinizing  with  heated  sulphuric  acid;  from  smithsonite 
by  not  effervescing  with  acids,  and  by  the  rectangular 
aspect  of  its  crystals  over  a  drusy  surface. 

Obs.  Occurs  with  galenite.  In  the  United  States  it  is 
found  at  Joplin  Creek,  Granby  Dist.,  Mine  La  Motte,  and 
ValleVs  Diggings,  Mo. ;  Perkiomen  and  Phcenixville  lead 
mines;  at  Friedensville  in  Saucon  Valley,  two  miles  from 
Bethlehem,  Pa.;  abundantly  at  Austin's  Mines,  Wythe 
Co.,  Va.  Valuable  as  an  ore  of  zinc. 

FranMinite,  an  ore  of  iron,  containing  manganese  and  zinc ;  see 
page  . 

General  Remarks. — The  metal  zinc  (spelter  of  commerce)  is  supposed 
to  have  been  unknown  in  the  metallic  state  to  the  Greeks  and  Romans. 
It  has  long  been  worked  in  China,  and  was  formerly  imported  in 
large  quantities  by  the  East  India  Company. 

The  principal  mining  regions  of  zinc  in  the  world  are  in  Upper 
Silesia,  at  Tarnowitz  and  elsewhere  ;  in  Poland  ;  in  Carinthia,  at 
Raibel  and  Bleiberg  ;  in  Netherlands  at  Limberg  ;  at  Altenberg,  near 
Aix-la-Chapelle  in  the  Prussian  province  of  the  Lower  Rhine  ;  at 
Vieille  Montagne  in  the  Liege  district,  Belgium  ;  in  England,  in 
Derbyshire,  Alstonmoor,  Mendip  Hills,  etc.;  in  the  Altai,  in  Russia; 


CADMIUM.  175 

besides  others  in  Italy,  Greece,  Sweden,  and  China.  In  the  U.  States, 
smithsonite  and  calamiric  occur  with  the  lead  ore  of  Missouri  in  large 
quantities.  They  were  formerly  considered  worthless  and  thrown 
aside,  under  the  name  of  "  dry  bone."  In  Tennessee,  Claiborne  Co., 
there  are  workable  mines.  Calamine  occurs  at  Friedensville,  Pa., 
along  with  massive  blende:  it  is  not  now  worked.  The  zincite,  wille- 
mite,  and  franklinite  of  Franklin,  N.  J.,  are  together  worked  as  a 
zinc  ore,  and  both  zinc  and  zinc  oxide  are  produced.  Blende  is 
sufficiently  abundant  to  be  worked  at  the  Wurtzboro'  lead  mine, 
Sullivan  Co.,  New  York  ,  at  Eaton  and  Warren,  in  N.  H;  at  Lubec, 
Me.;  at  Austin's  Mine,  Wythe  Co.,  Va.;  at  some  of  the  Missouri  lead 
mines. 

The  amount  of  zinc  produced  in  1885,  in  Europe,  was,  for  Belgium 
and  the  Rhine,  129,734  long  tons ;  Silesia,  79,623  ;  Poland,  5,000 ; 
Austria,  2,928 ;  France  and  Spain,  15,000  ;  Great  Britain,  23,100 ; 
United  States,  34,000  ;  making  in  all  about  290,000  long  tons.  In 
1884  Illinois  produced  about  16,000  tons;  Kansas,  over  7000 ;  Mis- 
souri, nearly  5000;  and  the  Eastern  and  Southern  States,  7050.  Market 
price  per  pound,  4  to  4'65  cents. 

Zinc  is  a  brittle  metal,  but  admits  of  being  rolled  into  sheets  when 
heated  to  about  212°  F.  In  sheets  it  is  extensively  used  for  roofing 
and  other  purposes,  it  being  of  more  difficult  corrosion,  much  harder, 
and  also  very  much  lighter  than  lead.  It  is  also  employed  largely  for 
coating  (that  is,  making  what  is  called  galvanized)  iron.  Its  alloys 
with  copper  (page  159)  are  of  great  importance. 

The  white  oxide  of  zinc  is  much  used  for  white  paint,  in  place  of 
white  lead;  and  also  in  making  a  glass  for  optical  purposes. 

An  impure  oxide  of  zinc,  called  cadmia,  often  collects  in  large  quan- 
tities in  the  flues  of  iron  and  other  furnaces,  derived  from  ores  of  zinc 
mixed  with  the  ores  undergoing  reduction.  A  mass  weighing  600 
pounds  was  taken  from  a  furnace  at  Bennington,  Vt.  It  has  been  ob- 
served in  the  Salisbury  iron  furnace,  and  at  Ancram,  in  New  Jersey, 
where  it  was  formerly  called  Ancramite. 


CADMIUM. 

Onty  two  ores  of  this  metal  are  known;  but  it  exists 
with  zinc  in  sphalerite,  smithsonite  and  calamine.  The 
cadmiferous  sphalerite  is  called  Przibramite.  The  metal 
cadmium  (discovered  by  Stromeyer  in  1818)  is  white  like 
tin,  and  is  so  soft  that  it  leaves  a  trace  upon  paper.  It 
-  f  uses  at  442°  F. 

GreenocJdte.  In  hexagonal  prisms;  light-yellow;  lustrous  and  nearly 
transparent;  H.  =  3-3 '5;  G.  =  4'8-5.  Bishopton,  Scotland;  Bohemia, 
on  blende;  Friedensville.  Lehigh  Co.,  Pa. 

Efjgonite.  In  translucent  orthorhombic  crystals;  light  grayish-brown; 
lustre  subadainantine;  H.  =4-5;B.B.  infusible;  supposed  to  be  a 
silicate  of  cadmium.  On  calamine  at  Altenberg. 


176 


DESCRIPTIONS   OF   MINERALS. 


TIN. 

Tin  has  been  reported  as  occurring  native  in  the  gold 
washings  of  the  Ural,  and  in  Bolivia.  There  are  two  ores, 
a  sulphide  and  an  oxide.  It  is  also  contained  in  some  ores 
of  niobium,  tantalum,  and  tungsten. 

Stannite.— Tin  Pyrites.    Sulplmret  of  Tin.     Tin  Sulphide. 

Commonly  massive,  or  in  grains.  Color  steel-gray  to 
iron-black;  streak  blackish.  Brittle.  H.  —  4.  G.  =  43- 
4-6. 

Composition.  Sulphur  30,  tin  27,  copper  30,  iron  13  —  100. 
.  Obs.  From  Cornwall,  where  it  is  often  called  bell-metal 
ore,  from  its  frequent  bronze-like  appearance ;  also  from 
Ireland  and  the  Erzgebirge. 


Tetragonal. 


pal 

Ne 


Cassiterite.— Tin  Ore.     Tin  Oxide. 

In  square  prisms  and  octahedrons;  often  in 
twins;  1  A  1  =  121°  40'; 
li  A 1*  (over  the  summit)  2. 

112°    10'    (over    a    ter- 
minal   edge)    133°  31'. 
Cleavage  indistinct.  Also 
massive,  and  in  grains. 
Color    brown,    black 
yellow;  lustre  of  crystals 
high  adamantine.  Streak 
ale  gray  to    brownish, 
[early    transparent    to 
opaque.    H.  =  6-7.    G.  of  light-colored,  6*4-6 '85;  of  dark, 
6-8-7-02. 

Composition.  Sn02  =  Oxygen  21*33,  tin  78'67  ;  often 
contains  a  little  iron,  and  sometimes  tantalum.  B.B.  alone 
infusible.  On  charcoal  with  soda,  a  globule  of  tin. 

Stream  tin  is  the  gravel-like  ore  found  in  debris  in  low 
grounds.  Wood  tin  occurs  in  botryoidal  and  reniform  shapes 
with  a  concentric  and  radiated  structure ;  and  toad's-eye  tin 
is  the  same  on  a  small  scale. 

Diff.  Has  some  resemblance  to  a  dark  garnet,  to  black 
zinc  blende,  and  to  some  varieties  of  tourmaline.  Distin- 
guished by  its  infusibility,  and  its  yielding  tin  before  the 


TIN.  177 

blowpipe  on  charcoal  with  soda.     Differs  from  blende  also 
in  its  superior  hardness. 

Obs.  Tin  ore  occurs  in  veins  in  granite,  a  quartzose 
gneiss,  and  mica  schist,  associated  often  with  wolfram, 
pyrite,  topaz,  tourmaline,  mica  or  talc,  and  albite.  Corn- 
wall is  one  of  its  most  productive  localities ;  also  worked  in 
Saxony,  at  Altenberg,  Geyer,  Ehrenfriedersdorf  and  Zinn- 
wald ;  in  Austria,  at  Schlackenwald  and  other  places ;  in 
Malacca,  Pegu,  China,  and  especially  the  Island  of  Banca 
in  the  East  Indies ;  in  Queensland  and  Northern  New  South 
Wales,  Australia,  in  large  quantities;  in  Greenland.  Oc- 
curs also  in  Galicia,  Spain;  at  Dalecarlia  in  Sweden;  in 
Eussia;  in  Mexico  at  Durango;  and  Bolivia.  In  the 
'United  States  found  sparingly  at  Chesterfield  and  Goshen, 
Mass. ;  at  Winslow,  Me. ;  Lyme  and  Jackson,  N.  H. ;  in  the 
eastern  corner  of  Eockbridge  Co.,  Va.;  Ashland,  Clay  Co., 
Ala.;  valuable  veins  in  the  Black  Hills,  Dakota,  in  the 
Harney  range;  in  the  Temescal  Eange,  and  at  San  Diego, 
Cal. ;  on  Jordan  E.,  Idaho;  in  Montana,  near  Helena;  Nig- 
ger Hill,  Wyoming. 

General  Remarks. — The  principal  tin  mines  now  worked  are  those 
of  Cornwall,  Banca,  Malacca,  and  Australia. 

The  Cornwall  mines  were  worked  long  before  the  Christian  era. 
Herodotus,  450  years  before  Christ,  is  believed  to  allude  to  the  tin 
islands  of  Britain  under  the  cabalistic  name  Cassiterides,  derived  from 
the  Greek  kassiteros,  signifying  tin.  The  Phoanicians  are  allowed  to 
have  traded  with  Cornubia  (as  Cornwall  was  called,  it  is  supposed 
^from  the  horn-like  shape  of  this  extremity  of  England).  The  Greeks 
residing  at  Marseilles  were  the  next  to  visit  Cornwall  or  the  isles  ad- 
jacent, to  purchase  tin;  and  after  them  came  the  Romans,  whose 
merchants  were  long  foiled  in  their  attempts  to  discover  the  tin  market 
of  their  predecessors. 

Carnden  says:  "  It  is  plain  that  the  ancient  Britons  dealt  in  tin  mines 
from  the  testimony,  of  Dioclorus  Siculus,  who  lived  in  the  reign  of 
Augustus,  and  Timaus,  the  historian  in  Pliny,  who  tells  us  that  the 
Britons  fetched  tin  out  of  the  Isle  of  Icta  (the  Isle  of  Wight),  in  their 
little  wicker  boats  covered  with  leather.  The  import  of  the  passage 
in  Diodorus  is  that  the  Britons  who  lived  in  those  parts  dug  tin  out  of 
a  rocky  sort  of  ground,  and  carried  it  in  carts  at  low  water  to  certain 
neighboring  islands;  and  that  from  thence  the  merchants  first  trans- 
ported it  to  Gaul,  and  afterwards  on  horseback  in  thirty  days  to  the 
springs  of  Eridanus,  or  the  city  of  Narbpna,  as  to  a  common  mart. 
JEthicus  too,  another  ancient  writer,  intimates  the  same  thing,  and 
adds  that  he  had  himself  given  directions  to  the  workmen."  In  the 
opinion  of  the  learned  author  of  the  Britannica  here  quoted,  and  others 
who  have  followed  him,  the  Saxons  seem  not  to  have  no  eddied  with 
the  mines,  or,  according  to  tradition,  to  have  employed  the  Saracensj 


178  DESCRIPTIONS   OF   MINERALS. 

for  the  inhabitants  of  Cornwall  to  this  day  call  a  mine  that  is  given 
over  working  Attal-Sarasin,  that  is,  the  leavings  of  the  Saracens. 

The  Cornwall  veins,  or  lodes,  mostly  run  east  and  west,  with  a  dip 
—hade,  in  the  provincial  dialect — varying  from  north  to  south;  yet 
they  are  very  irregular,  sometimes  crossing  each  other,  and  sometimes 
a  promising  vein  abruptly  narrows  or  disappears;  or  again  they  spread 
put  into  a  kind  of  bed  or  floor.  The  veins  are  considered  worth  work- 
ing when  but  three  inches  wide.  The  gangue  is  mostly  quartz,  with 
some  chlorite.  Much  of  the  tin  is  also  obtained  from  beds  of  loose 
stones  or  gravel  (called  shodes),  and  courses  of  such  gravel  or  tin  debris 
are  called  streams,  whence  the  name  stream  tin.  The  production  of 
tin  in  Great  Britain  in  1883  was  9307  tons,  valued  at  £735,189.  Ger- 
many yields  now  not  over  100  tons  annually ;  and  Austria,  Italy, 
Spain,  Russia,  each  less  than  this. 

The  Australian  mines  are  mainly  in  the  New  England  district  of 
Northern  New  South  Wales,  and  the  adjoining  part  of  Queensland, 
having  an  area  of  8500  sq.  m. ;  a  large  part  of  the  ore  goes  north 
through  Queensland.  The  value  of  the  tin  exported  in  1875  from 
Queensland  was  £100,740;  in  1881,  £2,168.790;  in  1882.  £560,590. 
New  South  Wales  produced,  in  1875,  £561,311,  corresponding  to  6058 
tons  of  tin  in  ingots,  besides  2022  tons  of  ore;  in  1883  the  amount  was 
nearly  9000  tons.  Tasmania  produced  in  1881  tin  to  the  value  of 
£375,775.  Banca  and  Malacca,  in  1882,  produced  over  15,000  tons. 

Tin  is  used  in  castings,  and  also  for  coating  other  metals,  especially 
iron  and  copper.  Copper  vessels  thus  coated  were  in  use  among  the 
Romans,  though  not  common.  Pliny  says  that  the  tinned  articles 
could  scarcely  be  distinguished  from  silver,  and  his  use  of  the  words 
incoquere  and  incoctilia  seems  to  imply,  as  a  writer  states,  that  the 
process  was  the  same  as  for  the  iron  wares  of  the  present  day,  by  im- 
mersing the  vessels  in  melted  tin.  Its  alloys  with  copper  are  mentioned 
on  page  159.  It  is  also  used  for  coating  copper. 

Tin  is  also  used  extensively  as  tinfoil ;  but  most  of  the  modern  tin- 
foil consists,  beneath  the  surface,  of  lead,  and  is  made  by  rolling  out 
plates  of  lead  coated  with  tin,  an  invention  of  Mr.  J.  J.  Crookes. 
With  quicksilver  it  is  used  to  cover  glass  in  the  manufacture  of  mir- 
rors. Tin  oxide  (dioxide),  obtained  by  chemical  processes,  is  employed, 
on  account  of  its  hardness,  in  making  a  paste  (called  "  putty  of  tin") 
for  polishing  hard  stones,  for  sharpening  fine  cutting  instruments, 
and  also  to  some  extent  in  the  preparation  of  enamels.  The  chlorides 
of  tin  are  important  in  the  precipitation  of  many  colors  as  lakes,  and 
in  fixing  and  changing  colors  in  dyeing  and  calico  printing.  The 
bisulphide  has  a  golden  lustre,  and  was  termed  aurum  musivum,  or 
mosaic  gold,  by  the  alchemists.  It  is  much  used  for  ornamental 
painting,  for  paper-hangings  and  other  purposes,  under  the  name  of 
bronze  powder. 

TITANIUM. 

Titanium  occurs  in  nature  combined  with  oxygen,  form- 
ing titanium  dioxide  or  titanic  acid,  and  also  in  oxygen 
combinations  with  iron  and  calcium,  and  in  some  silicates. 
It  has  not  been  met  with  native. 


TITANIUM.  179 

The  ores  are  infusible  alone  before  the  blowpipe,  or  nearly 
so.  Their  specific  gravity  is  between  3-0  and  4*5. 

Rutile. 

Tetragonal;  in  prisms  of  four,  eight,  or  more  sides,  with 
pyramidal  terminations;  often  acicular  and 
penetrating  quartz;  often  twinned  as  in  the 
figure  and  in  other  groupings  (p. 59;  1 A  1  =) 
123°  7£'.  Sometimes  massive.  Cleavage 
lateral,  somewhat  distinct. 

Color  reddish  brown  to  nearly  red;  streak 
very  pale  brown.  Lustre  submetallic-ada- 
mantine.  Transparent  to  opaque.  Brittle. 
H.  =  6-6-5.  G.  =  4-18-4-22;  black,  4-24-4-25. 

Composition.  Ti02  =  Oxygen  39,  titanium  61  =  100. 
This  composition  is  that  also  of  octahedrite  and  brookite 
(next  page);  the  species  differ  in  crystallization  and  other 
physical  characters.  Sometimes  contains  iron,  and  has 
nearly  a  black  color  (Nigrine).  B.B.  alone  unaltered; 
with  salt  of  phosphorus  a  colorless  bead,  which  in  the  re- 
ducing flame  becomes  violet  on  cooling. 

Diff.  The  peculiar  subadamantine  lustre  of  rutile,  and 
brownish-red  color,  in  splinters  much  lighter  red,  are  strik- 
ing characters.  It  differs  from  tourmaline,  idocrase,  and 
augite,  by  being  unaltered  when  heated  alone  before  the 
blowpipe;  and  from  tin  ore,  in  not  affording  tin  with  soda; 
from  sphene  in  its  crystals. 

Ob*.  Occurs  in  granite,  gneiss,  mica  schist,  syenyte,  and 
in  granular  limestone.  Sometimes  associated  with  hema- 
tite, as  at  the  Grisons.  Occurs  at  Yrieix,  .France;  Castile; 
Brazil;  Arendal,  Norway. 

In  the  United  States,  it  occurs  in  crystals  at  Warren, 
Me.;  Lyme  and  Hanover,  N.  H. ;  Barre,  Windsor,  Shel- 
burne,  Leyden,  Con  way,  Mass.;  Monroe  and  Huntington, 
Ct.;  near  Edenville,  Warwick,  Amity,  Kingsbridge,  and 
in  Essex  Co.  at  Gouverneur,  N.  Y. ;  in  Chester  Co.,  Pa.; 
District  of  Columbia,  at  Georgetown;  Buncombe  and  Alex- 
ander Cos.,  N.  C.;  Lincoln  and  Habersham  Cos.,  Ga.; 
Magnet  Cove,  Ark. 

Quartz  crystal  penetrated  by  long  acicular  crystals 
(Sagenite)  are  often  very  handsome  when  polished.  A  re- 
markable specimen  of  this  kind  was  obtained  in  Northern 
Vermont,  and  less  handsome  ones  are  not  uncommon;  they 

2o 


180  DESCRIPTIONS   OF   MINERALS. 

are  found  in  N.  Carolina.     Polished  stones  of  this  kind 
are  called  in  France  fleches  d9 amour  (love's  arrows). 

This  ore  is  employed  in  painting  on  porcelain,  and  quite 
largely  for  giving,  the  requisite  shade  of  color  and  enamel 
appearance  to  artificial  teeth;  some  kinds  make  fine 
though  nearly  opaque  gems. 

Octahedrite  (Anatase).  Tetragonal;  in  slender  nearly  transparent 
acute  octahedrons;  IA!  =  97°  51';  H.  =  5'5-6;  G.  =  3*8-3'95;  color 
brown.  Dauphiny;  the  Tyrol;  Brazil;  Smithfield,  R.  I.;  Brindle- 
town,  Burke  Co.,  N.  C. 

Brookite.  In  thin  hair-brown  flat  orthorhombic  crystals;  also  in 
thick  iron-black  crystals,  as  in  the  variety  called  Arkansite;  H.  = 
5-5-6.  Dauphiny;  Snpwdon  in  Wales;  Ellenville,  Ulster  Co.,  N.  Y.; 
Paris,  Me.;  gold  washings,  N.  C. ;  Magnet  Cove,  Ark.  (Arkansite.) 

Pseudobrookiie.  In  thin  tabular  brown  to  black  crystals  from 
Transylvania  and  Monte  Dore.  Much  like  brookite,  but  containing 
4-23  p.  c.  of  Fe2O3. 

Perofskite.  In  cubic  crystals,  light  yellow,  brown,  and  black; 
formula  (Ti,  Ca)2O3.  Urals;  Tyrol;  Magnet  Cove,  Ark. 

Besides  the  ores  here  described,  titanium  is  an  essential  constituent 
also  of  menaccanite  (titanic  iron),  and  of  the  silicates  litanite  or  sphene 
(p.  290),  keiihauite  (p.  291),  warwicldte ;  and  occurs  also  in  the  zir- 
conia  and  yttria  ores  aschyntte,  cerstedite,  and  polymignite,  and  in  some 
other  rare  species;  sometimes  in  pyrochlore. 

COBALT.    NICKEL. 

Cobalt  has  not  been  found  native.  The  ores  of  cobalt 
are  sulphides,  arsenides,  arseno-sulphides,  an  oxide,  a  car- 
bonate, a  phosphate,  and  an  arsenate;  and  nickel  is  often 
associated  with  cobalt  in  the  sulphides  and  arsenides.  The 
ores  having  a  metallic  lustre  vary  in  specific  gravity  from 
6*2  to  72;  are  nearly  tin-white  or  pale  steel-gray,  inclined 
to  copper-red  in  color.  The  ores  without  a  metallic  lustre 
have  a  clear  red  or  reddish  color,  and  specific  gravity  of 
nearly  3.  Cobalt  is  often  present  also  in  arsenopyrite  (or 
mispickel),  and  sometimes  in  pyrite. 

The  ores  of  nickel  are  sulphides,  arsenides,  arseno-sulph- 
ides,  and  antimono-sulphides,  a  sulphate,  carbonate,  sili- 
cates, arsenate;  and  the  metal  is  a  constituent  of  several 
cobalt  ores,  and  also  often  of  pyrrhotite  (magnetic  pyrites). 
Specific  gravity  between  3  and  8;  hardness  of  one,  3,  but 
mostly  between  5  and  6.  Those  of  metallic  lustre  resem- 
ble some  cobalt  ores;  but  they  do  not  give  a  deep-blue  color 
with  borax.  Alloys  of  nickel  and  iron  occur  in  meteorites 
(p.  189). 


COBALT.       NICKEL.  181 

SULPHIDES,  ARSENIDES,  ANTIMONIDES,  TET.LURIDES. 
Linneeite.— Cobalt  Sulphide.     Cobalt  and  Nickel  Sulphide. 

Isometric.  In  octahedrons  and  cubo-octahedrons;  also 
massive.  Color  pale  steel-gray,  tarnishing  copper-red. 
Streak  blackish  gray.  H.  =  5 -5.  G.  —  4-8-5. 

Composition.  Co3S4  =  Sulphur  42-0,  cobalt  58 -0  =  100  ; 
part  of  the  cobalt  replaced  by  nickel;  copper  sometimes 
present.  Siegenite  contains  30  to  40  per  cent,  of  nickel. 
B.B.  on  charcoal  yields  sulphurous  odor  and  a  magnetic 
globule ;  often  also  arsenical  fumes. 

Obs.  From  Sweden;  Siegen,  Prussia;  Mine  la  Motte, 
Mo.  (Siegenite) ;  Mineral  Hill,  Md.  Sometimes  called 
Cobalt  pyrites.  Carrollite  is  cobalt-copper  pyrites. 

Millerite.— Nickel  Sulphide.     Capillary  Pyrites. 

Ehombohedral.  Usually  in  capillary  or  needle-like  crys- 
tallizations; sometimes  like  wool;  often  in  divergent  tufts. 
Also  in  fibrous  crusts;  color  brass-yellow,  inclining  to 
bronze-yellow,  with  often  a  gray  iridescent  tarnish.  Streak 
bright.  Brittle.  H.  =  3-3'5.  G.  =  5  -65. 

Composition.  NiS  =  Sulphur  35-6,  nickel  64*4  =  100. 
In  the  open  tube  sulphurous  fumes.  B.B.  on  charcoal  fuses 
to  a  globule;  after  roasting,  gives,  with  borax,  and  salt  of 
phosphorus,  a  violet  bead  in  O.F.,  which  in  R.F.  becomes 
gray  from  reduced  metallic  nickel. 

Obs.  From  Joachimstahl,  Przibram,  Eiechelsdorf ;  Sax- 
ony; Cornwall;  at  the  Sterling  Mine,  Antwerp,  N.  Y.;  at 
the  Gap  Mine,  Lancaster  Co.,  Pa.;  at  St.  Louis,  Mo.,  in 
capillary  forms,  and  sometimes  wool-like,  in  cavities  in 
magnesian  limestone;  Nevada.  A  valuable  ore  of  nickel. 

Beyrichite.    Hexagonal?;  a  nickel  sulphide  with  Ni  56'79  p.  c. 
Potydymite.    In  isometric  octahedrons  ;  brilliant  metallic  ;  gray  ; 
nickel  sulphide.     Grunau,  Westphalia. 

/     -  '  » 

Smaltite.— Cobalt  Glance.     Chloanthite. 

Isometric.  In  octahedrons,  cubes,  dodecahedrons,  and 
other  forms;  see  Figs.  1,  2,  3,  page  18,  and  17,  27,  page 
21.  Cleavage  octahedral,  somewhat  distinct.  Also  reticu- 
lated; often  massive. 

Color  tin- white,  sometimes  inclining  to  steel-gray.  Streak 
grayish  black.  Brittle.  Fracture  granular  and  uneven. 
H.  =  5-5-6.  G.  =  6-4-6-9,  mostly;  also  7 -2. 


182  DESCRIPTIONS   OF  MINEKALS. 

Composition.  (Co,  ISTi)  As2;  the  ore  being  either  a  cobalt 
arsenide,  or  cobalt-nickel  arsenide;  and  graduating  into  the 
nickel  arsenide  called  Chloanthite.  The  cobalt  in  the  ore 
varies  from  23 '5  per  cent,  to  none;  iron  often  replaces 
part  of  the  other  metals. 

In  the  closed  tube  gives  metallic  arsenic;  in  the  open 
tube,  a  white  sublimate  of  arsenous  oxide,  and  sometimes 
traces  of  sulphurous  acid.  B.B.  on  charcoal  an  arsenical 
odor,  fuses  to  a  globule  which  gives  reaction  for  iron,  co- 
balt, and  nickel. 

Diff.  Arsenopyrite  (mispickel)  is  white  like  smaltite, 
but  yields  sulphur  as  well  as  arsenic,  and  in  a  closed  tube 
affords  the  arsenic  sulphides,  orpiment  and  realgar. 

Obs.  Usually  in  veins  with  ores  of  cobalt,  silver,  and 
copper.  Occurs  in  Saxony,  especially  at  Schneeberg  ;  also 
in  Bohemia,  Hessia,  and  Cornwall.  In  the  U.  States, 
found  sparingly  in  gneiss,  with  niccolite,  at  Chatham,  Ct. ; 
in  Gunnison  Co.,  Col. 

Cobaltite. 

Isometric.  Crystals  like  those  of  pyrite,  but  silver-white 
with  a  tinge  of  red,  or  inclined  to  steel-gray.  Streak  gray- 
ish black.  Brittle.  H.  =  5-5.  G.  =  6-6-3. 

Composition.  CoS2  +  CoAs2  —  CoAsS  =  Arsenic  45 '2, 
sulphur  19 '3,  cobalt  35 -5  —  100,  but  often  with  much  iron 
and  occasionally  a  little  copper.  Unaltered  in  the  closed 
tube;  but  in  the  open  tube,  yields  sulphurous  fumes  and  a 
white  sublimate  of  arsenous  oxide.  B.  B.  on  charcoal  yields 
sulphur  and  arsenic  and  a  magnetic  globule;  with  borax  a 
cobalt-blue  globule. 

Diff.  Unlike  smaltite  affords  sulphur,  and  has  a  reddish 
tinge  in  its  white  color. 

Obs.  From  Sweden,  Norway,  Siberia,  and  Cornwall. 
Most  abundant  in  the  mines  of  Wehna  in  Sweden,  first 
opened  in  1809. 

Niccolite. — Copper  Nickel.     Arsenical  Nickel. 

Hexagonal.  Usually  massive.  Color  pale  copper-red. 
Streak  pale  brownish-red.  Lustre  metallic.  Brittle.  H.  = 
5-5-5.  G.  =  7 -35-7 -67. 

Composition.  NiAs  =  Nickel  44,  and  arsenic  56  ;  part 
of  the  arsenic  may  be  replaced  by  antimony.  B.B.  gives 
off  arsenical  fumes,  and  fuses  to  a  pale  globule,  which 


COBALT.       NICKEL.  183 

darkens  on  exposure.  Assumes  a  green  coating  in  nitric 
acid,  and  is  dissolved  in  aqua-regia.  Arite  is  an  antimo- 
nial  variety  from  Balen,  Pyrenees. 

Diff.  Distinguished  from  pyrite  and  linnseite  by  its  pale 
reddish  shade  of  color,  and  also  its  arsenical  fumes,  and 
from  much  of  the  latter  by  not  giving  a  blue  color  with 
borax.  None  of  the  ores  of  silver  with  a  metallic  lustre 
have  a  pale  color,  excepting  native  silver  itself. 

Obs.  Accompanies  cobalt,  silver,  and  copper  ores  in  the 
mines  of  Saxony,  and  other  parts  of  Europe;  also  sparingly 
in  Cornwall.  Found  at  Chatham,  Ct.,  in  gneiss,  associated 
with  white  nickel  or  cloanthite;  in  Churchill  Co.,  Nev., 
abundant,  near  Lovelock's  station,  on  the  Central  Pacific 
E.  K. 

Skutterudite.    Cobalt  arsenide,  CoAs3.     Skutterud,  Norway. 

Safflorite  (Spathiopyrite).  Cobalt-iron  arsenide ;  orthorbombic  ;  tin- 
white.  Bieber,  Germany. 

Breithauptite  OT  Antimonial  Nickel.  Hexagonal;  pale  copper-red, 
inclining  to  violet;  H.  =  5 '5-6;  G.  =  7 '54  ;  NiSb  =  Antimony  67 '8, 
nickel  32-2  =  100.  Andreasberg. 

Oersdorffite  (Nickel  glance).  A  nickel  arsenosulpbicle;  NiS2  -f~  NiAs2 
=  NiAsS  —  Arsenic  45'5,  sulphur  19'4,  nickel  35'1,  but  varying  much 
in  composition  :  sulphur-white  to  steel-gray;  H.  =  5*5;  G.  =  5'6-6'9. 
Loos,  Sweden  ;  the  Hartz  ;  Styria  ;  Thuringia.  Sommwrugaite  is  an 
auriferous  kind  from  Hungary. 

Ullmannite  or  Nickel  Stibine.  An  antimonial  nickel  sulphide,  con- 
taining 25  to  28  p.  c.  of  nickel;  steel-gray,  inclining  to  silver  white;  in 
cubes,  and  massive;  H.  =  5-5'5;  G.  =  6'25-6'5.  Duchy  of  Nassau. 

Grunauite  or  Bismuth  Nickel.  A  sulphide  containing  31  to  38 '5  of 
sulphur,  10  to  14  per  cent,  of  bismuth,  with  22  to  40*7  of  nickel ; 
light  steel-gray  to  silver-white;  often  tarnished  yellowish;  H.  =  4'5  ; 
G.  =  5-13.  Altenkirchen,  Prussia. 

Melonite.  Nickel  telluride;  reddish  white.  Calaveras  and  Bowlder 
Cos.,  Cal. 

OXIDE. 
Asbolite.— Earthy  Cobalt,    Black  Cobalt  Oxide. 

Earthy,  massive.  Color  black  or  blue-black.  Soluble 
in  muriatic  acid,  with  an  evolution  of  fumes  of  chlorine. 

Obs.  Occurs  in  an  earthy  state  mixed  with  oxide  of  man- 
ganese as  a  bog  ore,  or  secondary  product.  Abundant  at 
Mine  La  Motte,  Missouri,  and  also  near  Silver  Bluff,  South 
Carolina.  The  analyses  vary  in  the  proportion  of  oxide  of 
cobalt  associated  with  the  manganese,  as  the  compound  is 
a  mere  mixture.  Sulphide  of  cobalt  occurs  with  the  oxide. 


184  DESCRIPTIONS   OF   MINERALS. 

The  Carolina  ores  afforded  cobalt  oxide  24,  manganese 
oxide  76.  The  ore  from  Missouri,  as  analyzed  by  B.  Silli- 
man,  afforded  40  per  cent,  of  cobalt  oxide,  with  oxides  of 
nickel,  manganese,  iron  and  copper. 

This  ore  has  been  found  abroad  in  France,  Germany, 
Austria,  and  England. 

The  ore  is  purified  and  made  into  smalt,  for  the  arts. 

Eeterogenite.  Black;  reniform;  contains  78  p.  c.  cobalt  oxide,  and 
21 '33  of  water.  Schneeberg. 

Heubackite.  Mixture  of  oxides  of  cobalt,  nickel  and  iron,  with 
water. 

ARSENATES,  SULPHATES,  CARBONATES,  SILICATES. 
Erythrite.— Cobalt  Bloom.    Hydrous  Cobalt  Arsenate. 

Monoclinic.  In  oblique  crystals  having  a  highly  perfect 
cleavage,  like  mica;  laminae  flexible  in  one  direction.  Also 
as  an  incrustation;  in  reniform  shapes;  stellate. 

Color  peach-red,  crimson-red,  rarely  grayish  or  green- 
ish; streak  a  little  paler,  the  dry  powder  lavender-blue. 
Lustre  of  laminae  pearly;  earthy  varieties  without  lustre. 
Transparent  to  subtranslucent.  H.  =  1*5— 2.  Gr.  =  2*95. 

Composition.  Co308As2  -j-  8aq  (or  3CoO  +  As206  +  8aq) 
=  Arsenic  acid  38*4,  oxide  of  cobalt  37*6,  water  24*0.  B.B. 
on  charcoal,  arsenical  fumes  and  fuses;  a  blue  glass  with 
borax. 

The  earthy  ore  is  sometimes  called  peach-blossom  ore, 
from  its  color;  and  red  cobalt  ochre.  Kottigite  is  a  kind 
containing  zinc. 

Diff.  Resembles  red  antimony,  but  that  species  wholly 
volatilizes  before  the  blowpipe.  Red  copper  ore  differs  in 
color  and  in  giving  a  blue  glass  with  borax;  moreover,  the 
color  of  the  copper  ore  is  more  sombre. 

Q~bs.  Occurs  with  ores  of  lead  and  silver,  and  other  cobalt 
ores,  at  Schneeberg,  Saxony;  Saalfield,  Thuringia;  Riech- 
elsdorf,  in  Hessia;  Dauphiny;  Cornwall;  Cumberland;  near 
Lovelock's  station  on  TJ.  P.  R.  R.,  Nevada;  Compton,  Cal. 

Valuable  as  an  ore  of  cobalt  when  abundant. 

Boselite.    Cobalt  arsenate;  rose-red;  triclinic.    Schneeberg. 
Cobaltomenite.     Cobalt  selenite.     Cacheuta,  S.  A. 
Annabergite.     Nickel  arsenate;  apple-green.    Allemont,  Dauphiny; 
Annaberg;  Riechelsdorf ;  Nevada. 

Cdbreriie.    Hydrous  nickel  arsenate.    Laurium,  Greece. 
Biebente  (Cobalt   Vitriol).    Flesh-red,  rose-red;  taste  astringent: 


COBALT.      NICKEL.  185 

CoO4S  +  7aq  (or  CoO  +  SO3  +  7aq)  =  Sulphuric  acid  28'4,  cobalt 
oxide  25'5,  water  46*1.  Bieber,  near  Hanau;  Salzburg;  Cbili. 

Morenosite  (Nickel  Vitriol).    NiO4S  +  7aq  ;  apple-green,  greenish. 

Lindaclterite.     Hydrous  nickel-copper  arsenatc. 

Zaratite  (Emerald  Nickel).  Incrusting,  minute  globular  or  stalac- 
titic;  bright  emerald-green;  lustre  vitreous;  transparent  or  nearly  so; 
H.  =  3-3-25  ;  G.  =  2'5-2'7  ;  nickel  carbonate,  containing  nearly  30 
per  cent,  of  water;  B.  B.  infusible  alone,  but  loses  its  color.  With 
chromite  on  serpentine,  Lancaster  Co.,  Pa. 

Reminr,'tonite.  Hydrous  cobalt  carbonate;  rose-colored.  Finks- 
burg,  Md. 

tipJierocobaUite.  Cobalt  carbonate,  CoO3C  (or  CoO  +  CO2);  black 
to  red.  Saxony. 

NICKEL  SILICATES,  Genthite^  is  a  hydrous  magnesium-nickel  sili- 
cate, pale  apple-green,  yielding  in  one  analysis  30  per  cent,  of  nickel 
oxide;  from  Tez.is,  Lancaster  Co.,  Pa.,  and  other  localities.  Rottisite, 
from  Rottis,  Voigtland,  is  similar.  Pimelite  is  an  impure  apple-green 
silicate,  affording  in  one  case  15 '6  per  cent,  of  nickel  oxide.  Alipite 
and  Avalite  are  similar;  so  also  Garnierite  (and  Noumeite),  from  New 
Caledonia,  and  worked  there  for  nickel.  A  similar  ore  occurs  8  m. 
from  Canonville  in  S.  Oregon,  in  serpentine. 

General  Remarks. — The  two  arsenical  ores  of  cobalt  afford  the 
greater  part  of  the  cobalt  of  commerce.  The  earthy  oxide  when 
abundant  is  a  profitable  source  of  the  metal.  Erythrite  (Cobalt 
Bloom)  occurs  abundantly  with  other  cobalt  ores  at  its  localities  in 
Saxony,  Thuringia  and  Hesse  Cassel.  Arsenopyrite  (mispickel)  yields 
at  times  5  to  9  per  cent,  of  cobalt.  Nearly  all  the  cobalt  used  in  the 
U.  States  is  imported.  Mine  La  Motte  afforded  $12,500  worth  in 
1882,  and  the  works  at  Camdeu,  Pa.,  about  3  times  this  amount.  The 
value  of  the  metal  is  a  little  less  than  $3  a  pound. 

Cobalt  is  never  employed  in  the  arts  in  a  metallic  state,  as  its  alloys 
are  brittle  and  unimportant.  It  is  chiefly  used  for  painting  on  porce- 
lain and  pottery,  and  for  this  purpose  it  is  mostly  in  the  state  of  an 
oxide,  or  the  silicated  oxide  called  smalt  and  azure.  Thenard's  blue, 
or  cobalt  ultramarine,  is  made  on  the  large  scale  by  heating  a  mixture 
of  phosphate  or  arsenate  of  cobalt  and  alumina.  Zaffre  is  an  impure 
oxide  obtained  in  the  calcining  of  the  ore  with  twice  its  weight  of 
sand;  and  from  it  the  smalt  and  azure  are  produced. 

Nickel  is  worked  in  Germany,  Austria,  Russia,  Sweden,  England, 
United  States,  and  New  Caledonia.  It  is  obtained  largely  from  the 
copper  nickel  (niccolite)  and  chloanthite,  or  from  an  artificial  product 
called  speiss  (an  impure  arsenide),  derived  from  roasting  ores  of  cobalt 
containing  nickel;  from  siegenite  (or  nickel-linnaeitc),  a  sulphide  of 
cobalt  and  nickel;  from  millerite,  in  part;  from  the  apple-green  sili- 
cate; and  largely  from  pyrrhotite  or  "magnetic  iron  pyrites."  At 
the  Gap  Mine,  near  Lancaster,  Pa.,  the  ore  is  pyrrhotite  with  miller- 
ite; and  the  nickel  produced  from  the  mine  in  1884  was  64,550  Ibs.; 
this  was  smelted  at  the  American  Nickel  Works,  at  Camden,  N.  J., 
the  only  nickel  works  in  the  U.  States.  In  Missouri,  the  ore  is  siege- 
nite; in  New  Caledonia,  chiefly  the  silicate. 

Nickel  often  occurs  with  chrome  ores  in  serpentine  rocks;  it  also 


186  DESCRIPTIONS   OF  MINEKALS. 

occurs  in  meteoric  iron,  forming  an  alloy  with  the  iron,  which  is  char- 
acteristic of  most  meteorites.  The  proportion  sometimes  exceeds  20 
per  cent. 

As  nickel  does  not  rust  or  oxidize  (except  when  heated),  it  is  supe- 
rior to  steel  for  the  manufacture  of  many  philosophical  instruments. 
An  alloy  of  copper,  nickel,  and  zinc  (one-sixth  to  one-third  nickel), 
constitutes  the  German  silver,  or  argentane. 

"  German  silver"  is  not  a  very  recent  discovery.  In  the  reign  of 
William  III.  an  act  was  passed  making  it  felony  to  blanch  copper  in 
imitation  of  silver,  or  mix  it  with  silver  for  sale.  "  White  copper" 
lias  long  been  used  in  Saxony  for  various  small  articles;  the  alloy 
employed  is  stated  to  consist  of  copper  88'00,  nickel  8*75,  sulphur 
with  a  little  antimony  0*75,  silex,  clay,  and  iron  1/75.  A  similar 
alloy  is  well  known  in  China,  and  is  smuggled  into  various  parts  of 
the  East  Indies,  where  it  is  called  packfong.  It  has  been  sometimes 
identified  with  the  Chinese  tutenague.  M.  Meurer  analyzed  the  white 
copper  of  China,  and  found  it  to  consist  of  copper  65 '24,  zinc  19 '52, 
nickel  13,  silver  2-5,  with  a  trace  of  cobalt  and  iron.  Dr.  Fyfe  ob- 
tained copper  40'4,  nickel  31  6,  zinc  25'4,  and  iron  2*6.  It  has  the 
color  of  silver,  and  is  remarkably  sonorous.  It  is  worth  in  China 
about  one  fourth  its  weight  of  silver,  and  is  not  allowed  to  be  carried 
out  of  the  empire. 

An  alloy  of  75  per  cent,  copper  and  25  per  cent,  nickel  is  the  mate- 
rial of  the  United  States  cent.  Switzerland,  Belgium,  Germany, 
Mexico,  and  Jamaica  also  use  a  nickel  alloy  for  coins. 

Nickel  is  largely  used  at  the  present  time  for  nickel-plating  by 
electro-deposition.  The  value  of  the  metal  in  commerce  rose  in  the 
years  1870  to  1875,  from  $1.25  to  $3.00  per  pound  ;  but  since  1880  it 
has  been  $1  to  $1.10. 

URANIUM. 

Uranium  ores  have  a  specific  gravity  not  above  10,  and  a 
hardness  below  6.  The  ores  are  either  of  some  shade  of  light 
green  or  yellow,  or  they  are  dark  brown  or  black  and  dull, 
or  submetallic  and  without  a  metallic  lustre  when  powdered. 
They  are  not  reduced  when  heated  with  carbonate  of  soda; 
and  the  brown  or  black  species  fuse  with  difficulty  on  the 
edges  or  not  at  all. 

Uraninite. — Pitchblende.    Uranium  Oxide. 

Isometric.  In  octahedrons  and  related  forms.  Also  mas- 
sive and  botryoidal.  Color  grayish,  brownish,  or  velvet- 
black.  Lustre  submetallic  or  dull.  Streak  black.  Opaque. 
H.  =  5*5.  G.  =,  when  unaltered,  9  "2-9 '3  (from  Branch- 
ville). 

Composition.  Branchville  crystals,  U  81*50,  9  13 '47, 
Pb  3-97,  Fe  0-40,  H20  0-88  =  100-22.  Mineral  usually 
altered  and  impure,  with  G.  6-4-8.  B.B.  infusible;  a  gray 


URANIUM.  187 

scoria  with  borax.     Dissolves  slowly  in  nitric  acid  when 
powdered. 

Obs.  Occurs  in  veins  with  ores  of  lead  and  silver  in  Sax- 
ony, Bohemia,  and  Hungary;  also  in  the  tin-mines  of  Corn- 
wall, near  Redruth.  In  the  United  States,  at  Branchville, 
in  brilliant  octahedrons ;  very  sparingly  at  Middletown  and 
Haddam,  Ct. ;  in  NT.  Carolina ;  on  the  north  side  of  Lake 
Superior  (Coracite);  inGilpin  Co.,  near  Central  City,  Col., 
with  torbernite  and  other  uranium  ores  (common  results  of 
its  alteration),  where,  in  1872,  a  large  body  of  it  was  thrown 
out  of  a  shaft,  and  3  tons  sold  in  England  for  $1.50  per 
pound. 

The  oxides  of  uranium  are  used  in  painting  upon  porce- 
lain, yielding  a  fine  orange  in  the  enamelling  fire,  and  a  black 
color  in  that  in  which  the  porcelain  is  baked.  Bohemia  is 
the  chief  source  of  it. 

Cleveite.  Hydrated  oxide  of  uranium,  iron,  erbium,  cerium, 
yttrium;  isometric,  like  spinel.  Norway.  Broggerite  is  related;  from 
Norway. 

Gummite.  An  amorphous  uranium  ore,  looking  like  gum,  of  a  red- 
dish or  brownish  color;  a  hydrous  uraninite.  Johanngeorgenstadt; 
N.  Carolina. 

Eliasite.  Like  gummite,  more  or  less  resin-like  in  aspect;  reddish- 
brown  to  black.  Elias  Mine,  Joachimstahl. 

Hatcheltolite.  Hydrous  niobo-tantalate  of  uranium;  in  isometric 
octahedrons;  resembles  pyrochlore  ;  G.  =  4'76-4'84.  Mitchell  Co., 
North  Carolina. 

Blomstrandite.     Hydrous  titano-niobate;  black.     Sweden. 

Torbernite. — Uranite.    Chalcolite.    Uran-Mica. 

Tetragonal.  In  square  tables,  thinly  foliated  parallel  to 
the  base,  almost  like  mica;  laminse  brittle. 

Color  emerald  and  grass-green;  streak  a  little  paler. 
Lustre  of  laminae  pearly.  Transparent  to  subtranslucent. 
H.  =  2-2-5.  G.=3-3-3-6. 

Composition.  A  uranium-copper  phosphate,  consisting  if 
pure  of  Phosphorus  pentoxide  15*1,  uranium  trioxide  61*2, 
copper  oxide  8  '4,  water  15  '3  =  100.  B.  B.  fuses  to  a  blackish 
mass,  and  colors  the  flame  green. 

Diff.  The  micaceous  structure,  bright  green  color  and 
square  tabular  form  of  the  crystals  are  striking  characters. 

Obs.  Occurs  with  uranium,  silver  and  tin  ores.  It  is 
found  at  St.  Symphorien,  in  splendid  crystallizations,  near 
Redruth  and  elsewhere  in  Cornwall;  in  the  Saxon  and 
Bohemian  mines ;  in  North  Carolina. 


188  DESCRIPTIONS  OF  MINERALS. 

Autunite.  Similar  to  torbernite  and  often  occurring  with  it; 
color  bright  citron-yellow;  a  uranium-calcium  phosphate;  G.  =  3-3*2. 
Near  Autun  in  France ;  sparingly,  Portland,  Middletown ;  good  at 
Branchville,  Ct.;  Acworth,  N.  H.;  Chesterfield,  Mass.;  and  in  N. 
Carolina. 

Uranospinite  is  an  autunite  containing  arsenic  instead  of  phos- 
phorus; and  Zeunerite,  a  torbernite  containing  arsenic  instead  of  phos- 
phorus. 

PhospJmranylite.  Hydrous  uranium-lead  phosphate;  lemon-yellow. 
Mitchell  Co.,  N.C. 

Samarskite,  Euxenite,  Annerodite.     See  p.  221. 

Johannite  or  Uranvitriol.  A  uranium  sulphate;  fine  emerald  green; 
taste  bitter.  Bohemia.  Uranochalcite,  Medijdite,  Zippeite,  Voglianite, 
TTraconite,  are  other  uranium  sulphates. 

Trogerite  and  Walpurgite  are  uranium  arsenates.  Voglite  and  Liebig- 
ite  are  uranium  carbonates. 

Uranocircite  (Baryturanite)  is  a  hydrous  barium-uranium  phosphate. 
Uranothallite  is  a  hydrous  uranium-lime  carbonate;  and  Schrockerin- 
gite  is  similar. 

Uranotil.  A  hydrous  uranium-calcium  silicate;  G.  =3-8-3'9; 
Saxony;  Mitchell  Co.,  N.  C.  Uranopilite,  a  hydrous  calcium-ura- 
nium silicate;  from  Saxony.  Randiie,  a  doubtful  yellow  uranium 
compound;  near  Philadelphia,  Pa.  Uranothorite  is  a  thorite  contain- 
ing uranium;  from  the  Champlain  iron  region,  N.  Y. 


IRON. 

Iron  occurs  native,  and  alloyed  with  nickel  in  meteoric 
iron.  Its  most  abundant  ores  are  the  oxides  and  sulphides. 
It  is  also  found  combined  with  arsenic,  forming  arsenides 
and  sulpharsenides ;  with  oxygen  and  other  metals,  as  chro- 
mium, aluminum,  magnesium  ;  and  in  the  condition  of  sul- 
phate, phosphate,  arsenate,  niobate,  tantalate,  silicate,  and 
carbonate,  of  which  the  last  is  an  abundant  and  valuable  ore. 
Its  ores  are  widely  disseminated.  The  oxides  and  silicates 
are  the  ordinary  coloring  ingredients  of  soils,  clays,  earth, 
and  many  rocks,  tingeing  them  red,  yellow,  dull  green,  brown, 
and  black. 

The  ores  have  a  specific  gravity  below  8,  and  the  ordinary 
workable  ores  seldom  exceed  5.  Many  of  them  are  infusible 
before  the  blowpipe,  and  nearly  all  minerals  containing  iron 
become  attractable  by  the  magnet  after  heating,  B.B.  in 
the  inner  flame,  when  not  so  before.  By  their  difficult 
fusibility,  the  species  with  a  metallic  lustre  are  distinguished 
from  ores  of  silver  and  copper,  and  also  more  decidedly  from 
these  and  other  ores  by  blowpipe  reaction. 


IRON.  189 

Native  Iron. 

Isometric.     Usually  massive  with  octahedral  cleavage. 

Color  and  streak  iron-gray.  Fracture  hackly.  Malleable 
and  ductile.  H.  =4-5.  G.  =  7 '3-7 '8.  Acts  strongly  on 
the  magnet. 

Obs.  Native  iron  occurs  in  grains  disseminated  through 
some  doleryte,  basalt,  and  other  related  igneous  rocks  (as 
in  Connecticut) ;  and  in  Greenland,  in  very  large  masses  in 
such  igneous  rocks,  the  largest  weighing  over  a  ton.  It  is 
suggested  by  J.  Lawrence  Smith,  that  the  iron  was  re- 
duced by  means  of  carbohydrogen  vapors,  taken  into  the 
rock  from  carbonaceous  rocks  passed  through  on  the  way  to 
the  surface. 

It  is  a  constituent  of  nearly  all  meteorites,  and  the  chief 
ingredient  in  a  large  part  of  them ;  and  in  this  state  it  is 
with  a  rare  exception  alloyed  with  nickel,  and  with  traces 
of  cobalt  and  copper.  The  Texas  meteorite,  of  Yale  Col- 
lege, weighs  1635  pounds;  the  Pallas  meteorite,  now  at 
Vienna,  originally  1600 ;  but  one  in  Mexico,  the  San  Gre- 
gorio  meteorite,  is  stated  to  weigh  five  tons ;  and  one  in  the 
district  of  Chaco-Gualamba,  S.  A.,  nearly  fifteen  tons. 
Meteoric  iron  often  has  a  very  broad  crystalline  structure, 
long  lines  and  triangular  figures  being  developed  by  putting 
nitric  acid  on  a  polished  surface.  The  coarseness  of  this 
structure  differs  in  different  meteorites,  and  serves  to  dis- 
tinguish specimens  not  identical  in  origin.  Nodules  of 
troilite  (FeS),  and  schreibersite  (iron  phosphide)  are  com- 
mon in  iron  meteorites.  Meteoric  iron  may  be  worked  like 
ordinary  malleable  iron.  The  nickel  diminishes  the  ten- 
dency to  rust.  But  some  kinds  contain  iron  chloride,  or 
are  open  in  texture,  and  rust  badly.  Chamasite,  Tcenite, 
Oktibehite,  Edmonsonite,  are  names  given  to  different  alloys 
of  nickel  and  iron  found  in  meteorites. 

SULPHIDES,  AKSENIDES,  TELLURIDES,  CHLOKIDES.^ 
Fyrite.— Iron  Pyrites.     Iron  Bisulphide. 

Isometric.  Usually  in  cubes,  the  striae  of  one  face  at  right 
angles  with  those  of  either  adjoining  face,  as  in  Fig.  1.  Also 
Figs.  2  to  7;  also  Figs.  8  to  15  on  page  20.  Fig.  6,  a  pentag- 
onal dodecahedron,  is  a  common  form.  Occurs  also  in  imi- 
tative shapes,  and  massive. 


190 


DESCRIPTIONS   OF   MINERALS. 


Color  brass-yellow ;  streak  brownish-black.  Lustre  often 
splendent  metallic.  Brittle.  H.  =  6-6 '5,  will  strike  fire 
with  steel.  G.  =  4-8-5-2;  purest  5-1-5-2. 

Composition.     FeSa  =  Sulphur   53 -3,   iron  46-7  =  100. 


B.B.  on  charcoal  gives  off  sulphur,  and  ultimately  affords 
a  globule  attractable  by  the  magnet. 

Pyrite  often  contains  a  minute  quantity  of  gold,  and  is 
then  called  auriferous  pyrite.  See  under  Gold.  Nickel, 
cobalt,  and  copper  occur  in  some  pyrite. 

Diff.  Distinguished  from  copper  pyrites  in  being  too  hard 
to  be  cut  by  a  knife,  and  also  in  its  paler  color.  The  ores 
of  silver  at  all  resembling  pyrite  are  steel-gray  or  nearly 
black ;  and  besides,  they  are  easily  scratched  with  a  knife 
and  quite  fusible.  Gold  is  sectile  and  malleable. 

Ols.  Pyrite  is  one  of  the  most  common  of  ores.  Occurs 
in  rocks  of  all  ages.  Cornwall,  Elba,  Piedmont,  Sweden, 
Brazil,  and  Peru  have  afforded  magnificent  crystals.  Alston 
Moor,  Derbyshire,  Kongsberg  in  Norway,  are  well-known 
localities.  It  has  also  been  observed  in  the  Vesuvian  lavas, 
and  in  many  other  igneous  rocks.  It  is  mined  largely  in 
Spain  and  Portugal,  particularly  at  the  Rio  Tinto  mine. 

Fine  crystals  have  been  met  with  at  Rossie,  N.  Y.,  and 
at  many  other  places  in  that  State  ;  also  in  each  of  the  New 
England  States  and  in  Canada ;  in  New  Jersey,  Pennsylvania, 


IKON.  191 

Virginia,  North  Carolina,  Georgia,  in  Colorado,  Wyoming, 
and  the  States  west.  It  occurs  in  all  gold  regions,  and  is 
one  source  of  gold.  A  vein  is  worked  in  Kome,  near  Char- 
lemont,  Mass.;  several  in  Louisa  Co.,  Va.;  in  Georgia; 
at  Capelton,  Canada. 

^fcThis  species  is  of  high  importance  in  the  arts,  although 
not  affording  good  iron  on  account  of  the  difficulty  of  sep- 
arating all  the  sulphur.  It  affords  the  greater  part  of  the 
sulphate  of  iron  (green  vitriol  or  copperas)  and  sulphuric 
acid  (oil  of  vitriol)  of  commerce,  and  also  a  considerable 
portion  of  the  sulphur  and  alum.  To  make  the  sulphate 
the  pyrites  are  sometimes  heated  in  clay  retorts,  by  which 
about  17  per  cent,  of  sulphur  is  distilled  over  and  collected. 
The  ore  is  then  thrown  out  into  heaps,  exposed  to  the  at- 
mosphere, when  a  change  ensues  by  which  the  remaining 
sulphur  and  iron  become  through  oxidation  sulphate  of  iron. 
The  material  is  lixiviated,  and  partially  evaporated,  prepar- 
atory to  its  being  run  off  into  vats  or  troughs  to  crystallize. 
In  other  instances,  the  ore  is  coarsely  broken  up  and  piled 
in  heaps  and  moistened.  Fuel  is  sometimes  used  to  com- 
mence the  process,  which  afterwards  the  heat  generated 
continues.  Decomposition  takes  place  as  before,  with  the 
same  result.  Cabinet  specimens  of  pyrite,  especially  the 
granular  or  amorphous  masses,  often  undergo  a  spontane- 
ous change  to  the  sulphate,  particularly  when  the  atmos- 
phere is  moist. 

Pyrite,  owing  to  its  tendency  to  oxidation,  and  its  very 
general  distribution  in  rocks  of  all  kinds  and  ages,  is  one  of 
the  chief  sources  of  the  disintegration  and  destruction  of 
rocks.     No  granite,  sandstone,  slate,  or  limestone,  contain- 
ing it  is  fit  for  architectural  purposes  or  for  any  outdoor   y 
use.     The  same  destructive  effects  come  from  pyrrhotite  f^inr 
and  marcasite,  which  also  are  widely  diffused. 

The  name  pyrites  is  from  the  Greek  pur,  fire ;  because,      / 
as  Pliny  states,  "there  was  much  fire  in  it,"  alluding  to 
its  striking  fire  with  steel.     This  ore  is  the  mundic  of 
miners. 

Marcasite  or  White  iron  pyrites.  Like  pyrite  in  composition,  but 
orthorbpmbic;  /  A  /=  106°  36';  color  a  little  paler;  more  liable  to  de- 
composition; bardness  tbe  same;  G.  =  4*6-4'85.  Radiated  pyrites,  He- 
patic pyrites,  Cocksc-omb  pyrites  (alluding  to  its  crested  shapes),  and 
Spear  pyrites,  are  names  of  some  of  its  varieties.  In  crystals  at  War- 
wick and  Pbillipstown,  N.  Y. ;  massive  at  Cummington,  Mass. ;  Mon- 
roe, Trumbull,  East  Haddam,  Ct;  Haverhill,  N.  H. 


192 


DESCRIPTIONS   OF   MINERALS. 


Fyrrhotite. — Magnetic  Pyrites.    Iron  Sulphide. 

Hexagonal.     In  tabular  hexagonal  prisms,  and  massive. 

Color  between  bronze-yellow  and  copper-red ;  streak  dark 
grayish  black.  Brittle.  H.  =  3'5-4-5.  Gk  =  4-5-4'65. 
Slightly  attracted  by  the  magnet.  Liable  to  speedy  tarnish. 

Composition.  Fe7S8=:  Sulphur  39'5,  iron  60*5.  It  is 
often  a  valuable  ore  of  nickel,  containing  sometimes  3  to  5 
per  cent,  of  this  metal.  B.  B.  on  charcoal  in  the  outer  flame 
it  is  converted  into  red  oxide  of  iron.  In  the  inner  flame  it 
fuses  and  glows,  and  affords  a  black  magnetic  globule,  which 
is  yellowish  on  a  surface  of  fracture. 

Diff.  Its  inferior  hardness  and  shade  of  color,  and  its 
magnetic  quality  distinguish  it  from  pyrite ;  and  its  pale- 
ness of  color  from  chalcopyrite  or  copper  pyrites. 

Obs.  Found  at  Kongsberg,  Norway;  Andreasberg  in  the 
Hartz ;  massive  in  Cornwall ;  Saxony;  Siberia ;  the  Hartz ; 
also  at  Vesuvius. 

In  the  United  States  it  is  met  with  at  Trumbull  and 
Monroe,  New  Fairfield,  and  Litchfield,  Ct. ;  New  Marlboro 
and  elsewhere,  Mass. ;  Strafford  and  Shrewsbury,  Vt. ;  Cor- 
inth, .N.  H. ;  Brewster,  etc.,  N.  Y. ;  Lancaster,  Pa.,  where 
it  is  worked  for  nickel ;  Canada,  at  Elizabethtown,  in  crys- 
tals. It  is  used  for  making  green  vitriol  and  sulphuric  acid, 
like  pyrite. 

Troilite.     Like  pyrrhotite,  but  having  the  formula  FeS ;  occurs 
only  in  meteorites. 
Schreibersite.    Iron-nickel  phosphide.    In  meteorites. 

Arsenopyrite.— Mispickel.    Arsenical  Iron  Pyrites. 

Orthorhombic ;  /A/ =111°  40'  to  112°.  In  rhombic 
prisms,  with  cleavage  parallel  to  /. 
Crystals  sometimes  elongated  hori- 
zontally, producing  a  rhombic  prism 
of  100°  nearly,  with  /  and  /  the  end 


planes.     Also  massive. 
Color    silver- white, 
grayish     black. 
Brittle.       H.  = 
6-3. 

Composition. 
46-0,  sulphur  19'6,  iron  34'4  =  200 


Streak    dark 
Lustre     shining. 
G.=5-67- 


FeAsS  =  Arsenic 
A  cdbaltic  variety 


contains  4  to  9  per  cent,  of  cobalt  in  place  of  part  of  the 


193 

iron ;  Danaite  of  New  Hampshire  consists  of  Arsenic  41-4, 
sulphur  17'8,  iron  32*9,  cobalt  6*5.  B.B.  affords  arsenical 
fumes,  and  a  globule  of  iron  sulphide  attractable  by  the 
magnet.  In  the  closed  tube  a  sublimate  of  arsenic  sulphide. 
Gives  fire  with  a  steel  and  emits  a  garlic  odor. 

Diff.  Resembles  arsenical  cobalt,  but  is  much  harder,  it 
giving  fire  with  steel ;  differs  also  in  yielding  a  magnetic 
globule  B.B. 

Ols.  Found  mostly  in  crystalline  rocks,  and  common 
with  ores  of  silver,  lead,  iron,  or  copper.  Worked  for  its 
arsenic,  and  sometimes  also  for  cobalt  and  gold.  Abundant 
at  Freiberg,  Munzig,  and  elsewhere  in  Europe,  and  also  in 
Cornwall,  England. 

In  crystals,  at  Franconia,  Jackson,  and  Haverhill,  N.  H. ; 
at  Blue  Hill  Bay,  Corinth,  Newfield,  and  Thomaston, 
Me. ;  at  Waterbury,  Vt. ;  massive  at  Worcester  and  Sterling, 
Mass.;  at  Franklin,  N.  J.;  in  Lewis,  Essex  Co.,  and  near 
Edenville  and  elsewhere  in  Orange  Co.,  in  Kent,  Putnam 
Co.,  N".  Y.;  at  Deloro,  Canada,  in  crystals,  and  worked  for 
arsenic. 

Leucopyrite.  Arsenical  iron  FeAs2.  Resembles  the  preceding  in 
color  and  in  its  crystals;  has  less  hardness  and  higher  specific  gravity; 
H.  =  5-5-5;  G.  =  6'8-8'71.  Contains  arsenic  72'8,  iron  27 '2,  with  some 
sulphur.  From  Styria,  Silesia,  and  Carinthia.  Nickeliferous  from 
Gunnison  Co.,  Col. 

Lollingile.  Another  iron  arsenide,  Fe2As3  =  Arsenic  66*8,  iron  33*2; 
G.  =  6-2-7-45. 

Berthierite.     An  iron  sulphantimonite. 

Orileyite.     A  doubtful  steel-gray  iron-copper  arsenide.     Burmah. 

FeiTotellurite.  Iron  tellurite,  FeO4Te  ;  tufts  of  minute  prisms  ; 
yellow,  greenish.  Keystone  Mine,  Col. 

Lawrencite.  Iron  protochloride.  The  Greenland  native  iron,  and 
one  cause  of  its  rapid  oxidization.  Named  after  J.  Lawrence  Smith. 
Stagmatite  is  the  same. 

Molysite.     Iron  chloride,  FeCl3.     Vesuvius. 

Kremersite.    Iron-potassium  amrr  onium  chloride.    Vesuvius. 

Eryihrosiderite.  Hydrous  iron-potassium  chloride.  Vesuvius. 
Douglassite. 

Sidtrazote.  Iron  nitride,  Fe6N2 ;  an  incrustation ;  lustre  steel-like. 
Mt.  Etna. 

OXIDES. 
Hematite. — Specular  Iron  Ore.     Iron  Sesquioxide. 

Rhombohedral ;  R  A  R  =  86°  10'  (Fig.  1).     Crystals  oc- 
casionally thin  tabular.    Cleavage  usually  indistinct.    Often 
13 


194  DESCRIPTIONS   OF   MINERALS. 

massive  granular ;  sometimes  lamellar  or  micaceous.     Also 
pulverulent  and  earthy. 

Color  dark  steel-gray  or  iron-black.     Lustre  when  crys- 
tallized splendent.     Streak-powder  cherry-red  or  reddish- 


brown.  The  metallic  varieties  pass  into  a  red  earthy  ore 
called  red  ochre,  having  none  of  the  external  characters  of 
the  crystals,  but  like  them  when  they  are  pulverized.  G.  = 
4  -5-5  *3.  Hardness  of  crystals  5  '5-6  •?.  Sometimes  slightly 
attracted  by  the  magnet. 


VARIETIES. 

Specular  iron.     Lustre  perfectly  metallic. 

Micaceous  iron.     Structure  foliated. 

Red  hematite.     Submetallic,  or  unmetallic,  brownish  red. 

Red  ochre.     Soft  and  earthy,  and  often  containing  clay. 

Red  chalk.  More  firm  and  compact  than  red  ochre,  and 
of  a  fine  texture. 

Jaspery  clay  iron.  A  hard  impure  siliceous  clayey  ore, 
and  having  a  brownish  red  jaspery  look  and  compactness. 

Clay  iron  stone.  The  same  as  the  last,  the  color  and  ap- 
pearance less  like  jasper.  But  this  is  one  variety  only  of 
what  is  called  "  clay  iron  stone,"  a  name  covering  also  a  re- 
lated variety  of  siderite  and  limonite. 

Lenticular  argillaceous  ore.  An  oolitic  red  ore,  consist- 
ing of  small  flattened  grains. 

Mar  tit  e  is  hematite  in  octahedrons,  derived,  it  is  supposed, 
from  the  oxidation  of  magnetite. 

Composition.  £e03  =  Oxygen  30,  iron  70  =  100.  B.B. 
alone  infusible  ;  in  the  inner  flame  becomes  magnetic. 

Diff.  The  red  powder  of  this  mineral,  and  the  magnetism 
which  is  so  easily  induced  in  it  by  the  reduction  flame  dis- 
tinguish hematite  from  all  other  ores .  The  word  hematite, 
from  the  Greek  haima,  blood,  alludes  to  the  color  of  the 
powder.  The  powder  of  magnetite  is  black. 


IRON.  195 

Obs.  Occurs  in  crystalline  and  stratified  rocks  of  all  ages. 
The  more  extensive  beds  abound  in  Archaean  rocks;  while  the 
argillaceous  varieties  occur  in  stratified  rocks,  being  often 
abundant  in  coal  regions  and  among  other  strata.  Crys- 
tallized specimens  are  found  also  in  some  lavas,  as  a  volcanic 
product. 

Splendid  crystallizations  of  this  ore  come  from  Elba,  whose 
beds  were  known  to  the  Eomans ;  also  from  St.  Gothard  ; 
Arendal,  Norway;  Longbanshyttan,  Sweden ;  Lorraine  and 
Dauphiny ;  Brazil  (martite  in  part).  Etna  and  Vesuvius 
afford  handsome  specimens. 

In  the  United  States  an  abundant  ore.  The  two  Iron 
Mountains  of  Missouri,  situated  90  miles  south  of  St.  Louis, 
consist  mainly  of  this  ore,  piled  te  in  masses  of  all  sizes  from 
a  pigeon's  egg  to  a  middle-sized  church ;"  one  300  feet  high, 
the  other,  the  "  Pilot  Knob/'  700  feet.  Large  beds  occur 
in  Essex,  St.  Lawrence,  and  Jefferson  Cos. ,  N.  Y.;  at  Mar- 
quette,  Mich.;  the  micaceous  variety,  at  Hawley,  Mass., 
Piermont,  N.  H.,  and  in  Stafford  County,  Va.;  lenticular 
argillaceous  ore  abundantly  in  Oneida,  Herkimer,  Madison, 
and  Wayne  Cos.,  N.  Y.,  constituting  one  or  two  beds  of  the 
Clinton  group  (Upper  Silurian),  in  a  compact  sandstone ; 
and  the  same  is  found  in  Pennsylvania  and  south  to  Ala- 
bama, and  also  in  "Wisconsin ;  it  contains  50  per  cent,  of 
oxide  of  iron,  with  about  25  of  carbonate  of  lime  and  more 
or  less  magnesia  and  clay.  The  coal  region  of  Pennsylvania 
affords  abundantly  the  clay  iron  ores,  but  they  are  mostly 
either  the  argillaceous  carbonate  or  limonite. 

Much  of  the  Marquette  ore  is  martite ;  and  the  Cerro  de 
Mercado,  of  Mexico,  is  spoken  of  as  a  mountain  of  mar- 
tite. 

Valuable  as  an  iron  ore,  though  less  easily  worked  when 
pure  and  metallic  than  the  magnetic  and  hydrous  ores.  Pul- 
verized red  hematite  is  used  for  polishing  metal.  Red  chalk 
is  a  well-known  material  for  red  pencils. 

Menaccanite.— Ilmenite.     Titanic  Iron.    Washingtonite. 

Rhombohedral ;  R  A  R  =  85°  31'.  Often  in  thin  plates 
or  seams  in  quartz;  also  in  grains.  Crystals  sometimes 
very  large  and  tabular. 

Color  iron-black.  Streak  submetallic.  Lustre  metallic  or 
submetallic.  H.  =  5-6.  G.  •=  4 -5-5.  Acts  slightly  on 
the  magnetic  needle. 


196  DESCRIPTIONS   OF   MINERALS. 

Composition.  Like  that  of  hematite,  except  that  part  of 
the  iron  is  replaced  by  titanium ;  the  amount  replaced  is 
very  variable.  Infusible  alone  before  the  blowpipe. 

biff.  Near  hematite,  but  its  powder  is  not  red. 

0,bs.  In  Warwick,  Amity,  and  Monroe,  Orange  Co.,  N.Y. 
Crystals,  an  inch  in  diameter ;  near  Edenville  and  Green- 
wood Furnace  ;  at  South  Royalston  and  Goshen,  Mass. ;  at 
Washington,  South  Britain,  and  Litchfield,  Ct.;  at  Westerly, 
R.  I. ;  Magnet  Cove,  Ark  ;  in  Canada. 

It  is  of  no  value  in  the  arts,  and  is  a  deleterious  constitu- 
ent of  many  iron  ores. 

Magnetite. — Magnetic  Iron  Ore. 

Isometric.  Often  in  octahedrons  (Fig.  1),  and  dodecahe- 
drons (Fig.  2).  Cleavage  oc- 
tahedral; sometimes  distinct. 
Also  granularly  massive. 
Occasionally  in  dendritic 
forms  between  the  folia  of 
mica. 

Color  iron-black.     Streak 
black.  Brittle.  H.=5-5-65. 
G.  =5-0-5-1.      Strongly  at- 
attracted  by  the  magnet,  and  sometimes  having  polarity. 

Composition.  FeFe04  -  £eO+Fe03  =  Oxygen  27'6,  iron 
72  -4  =  100.  Infusible  before  the  blowpipe.  Yields  a  yellow 
glass  when  fused  with  borax  in  the  outer  flame. 

Diff.  The  black  streak  and  strong  magnetism  distinguish 
this  species  from  the  following. 

Obs.  Magnetic  iron  ore  occurs  in  extensive  beds,  and  also 
in  disseminated  crystals.  It  is  met  with  in  granite,  gneiss, 
mica  schist,  clay  slate,  syenyte,  hornblende,  and  chlorite 
schist ;  and  also  sometimes  in  limestone. 

The  beds  at  Arendal,  and  nearly  all  the  Swedish  iron  ore, 
consist  of  massive  magnetic  iron.  At  Dannemora  and  the 
Taberg  in  Southern  Sweden,  and  also  in  Lapland  at 
Kurunavara  and  Gelivara,  there  are  mountains  composed 
of  it. 

In  the  U.  States  it  constitutes  extensive  beds,  in  Ar- 
chaean rocks,  in  Warren,  Essex,  Clinton,  Orange,  Putnam, 
Saratoga,  and  Herkimer  Cos.,  N.  Y.;  and  in  Sussex  and 
Warren  Cos.,  N.  J.  Smaller  deposits  occur  in  the  several 
New  England  States  and  Canada.  Also  found  at  Magnet 


IRON.  197 

Cove,  Ark.;  in  Sierra  Co.,  CaL;  with  hematite  in  the  Iron 
Mountains  of  Missouri. 

/  Masses  of  this  ore,  in  a  state  of  magnetic  polarity,  consti- 
tute what  are  called  lodesfoiicsor  native  magnets.  They  are 
met  with  in  many  beds  of  the  ore  :  in  Siberia  ;  the  Hartz  ; 
the  Island  of  Elba ;  at  Marshall's  Island,  Me. ;  near  Provi- 
dence, E.  L;  at  Magnet  Cove,  Ark.  The  lodestone  is 
called  magncs  by  Pliny,  from  the  name  of  the  country, 
Magnesia  (a  province  of  ancient  Lydia),  where  it  was 
found ;  and  it  hence  gave  the  terms  magnet  and  magnetism 
to  science. 

Franklinite. 

Isometric.  In  octahedral  and  dodecahedral  crystals ;  also 
coarse  granular  massive.  Color  iron-black.  Streak  dark 
reddish  brown.  Brittle.  H.  =5*5-6 -5.  G.  =  4-5-5-1. 
Usually  feebly  attracted  by  the  magnet. 

Composition.  General  formula  like  that  of  magnetite, 
RB04,  but  having  zinc  and  manganese  replacing  part  of  the 
iron,  as  indicated  in  the  formula  (Fe,  Zn,  Mn)  (¥e,  Mn)  04. 
A  common  variety  corresponds  to  Fea03  67*6,  FeO  5*8,  ZnO 
6-9,  MnO  9-7  =  100. 

B.B.  with  soda  on  charcoal  a  zinc  coating;  a  soda  bead 
in  the  outer  flame  is  colored  green  by  the  manganese. 

Diff.  Kesembles  magnetic  iron,  but  the  exterior  color  is  a 
more  decided  black.  The  streak  is  reddish  brown,  and  the 
blowpipe  reactions  are  distinctive. 

Obs.  Abundant  at  Sterling  and  Hamburg,  Sussex  Co., 
N.  J. ;  near  Franklin  Furnace,  crystals  sometimes  4  in.  in 
diameter.  Amorphous  at  Altenberg,  near  Aix-la-Chapelle. 

Jacobsite.  Isometric  octahedrons ;  Fc,  Mn,  MnO  ;  magnetic  ;  Swe- 
den. 

Chromite.— Cliromic  Iron. 

Isometric.  In  octahedrons ;  cleavage  none.  Usually 
massive,  and  breaking  with  a  rough  unpolished  surface. 

Color  iron-black,  brownish  black.  Streak  dark  brown. 
Lustre  submetallic ;  often  faint.  H.  =  5 -5.  G.  =  4-32-4-6. 
In  small  fragments  attractable  by  the  magnet. 

Composition.  General  formula  RB04,  as  for  magnetite, 
with  part  of  the  iron  replaced  by  chromium.  Analysis  gives 
Iron  protoxide  32,  chromium  sesquioxide  68  =  100  ;  alumi- 
nium and  magnesium  also  commonly  present,  replacing 


198  DESCRIPTIONS   OF  MINERALS. 

the  other  constituents.  B.B.  infusible  alone;  with  borax 
a  beautiful  green  bead. 

This  ore  usually  possesses  less  metallic  lustre  than  the 
other  black  iron  ores. 

Obs.  Occurs  usually  in-  serpentine  rocks,  in  imbedded 
masses  or  veins.  Some  of  the  foreign  localities  are  the 
Gulsen  Mountains  in  Styria;  the  Shetland  Islands;  the 
department  of  Var  in  France  ;  Silesia  ;  Bohemia,  etc. 

At  Bare  Hills,  Soldier's  Delight,  and  Owing's  Mills,  near 
Baltimore,  at  Cooptown  in  Harford  Co.,  and  north  part  of 
Cecil  Co.,  Md. ;  in  Townsend  and  Westfield,  Vt. ;  at  Chester 
and  Blandf  ord,  Mass. ;  at  Wood's  Mine,  near  Texas,  Lancas- 
ter Co.,  and  in  West  Branford,  Chester  Co.,  Pa.;  Jackson 
Co.,  N.  C.;  at  Bolton  and  Ham,  Canada  East;  San  Luis 
Obispo,  Napa,  Del  Norte,  Sonoma  (near  New  Idria),  and 
Tuolumne  Cos. ,  Gal. ;  at  Seattle  in  Wyoming. 

The  compounds  of  chromium,  which  are  extensively  used 
as  pigments,  are  obtained  chiefly  from  this  ore;  and  the 
California  mines  afford  nearly  all  that  is  used  in  the  U. 
States ;  about  2500  tons  were  mined  in  1882.  The  ore  is 
shipped  to  Baltimore,  and  there  nearly  all  is  made  into  the 
bichromate  for  calico-printing  and  other  purposes.  Chrome 
green  and  chrome  yellow,  for  use  as  pigments,  are  also 
manufactured  there.  'About  a  third  of  the  ore  used  at  Balti- 
more, or  near  2,000,000  Ibs.,  is  imported  from  Scotland. 

Daubreelite.    A.  black  chromium  sulphide.    From  meteorites. 

Limonite. — Brown  Hematite. 

Usually  massive ;  often  smooth  botryoidal  or  stalactitic, 
with  a  compact  fibrous  structure  within.  Also  earthy. 

Color  dark  brown  and  black  to  ochre-yellow ;  streak  yel- 
lowish brown  to  dull  yellow.  Lustre  when  black  sometimes 
submetallic ;  often  dull  and  earthy ;  on  a  surface  of  fracture 
frequently  silky.  H.  =  5-5'5.  G.  =  3 -6-4. 

The  following  are  the  principal  varieties  : 

Brown  hematite.  The  botryoidal,  stalactitic  and  asso- 
ciated compact  ore. 

Brown  ochre,  Yellow  ochre.  Earthy  ochreous  varieties 
of  a  brown  or  yellow  color. 

Brown  and  Yellow  clay  iron  stone.  Impure  ore,  hard 
and  compact,  of  a  brown  or  yellow  color. 

Bog  iron  ore.  A  loose  earthy  ore  of  a  brownish  black 
color,  occurring  in  low  grounds. 

\J\J(  tr 


IROH.  199 

Composition.  Fe09H6(=  2Fe03+  3H,0)  =  Iron  sesquiox- 
ide  85*6,  water  14-4=  100;  or  a  hydrous  iron  sesquioxide, 
containing,  when  pure,  about  two  thirds  its  weight  of  pure 
iron.  B.B.  blackens  and  becomes  magnetic;  with  borax  in 
the  outer  flame  a  yellow  glass. 

Diff.  A  much  softer  ore  than  either  of  the  two  preceding, 
and  peculiar  in  its  frequent  stalactitic  forms,  and  in  its  af- 
fording water  when  heated  in  a  glass  tube. 

Obs.  Occurs  connected  with  rocks  of  all  ages,  but  appears, 
as  shown  by  the  stalactitic  and  other  forms,  to  have  resulted 
in  all  cases  from  the  decomposition  of  other  iron-bearing 
rocks  or  minerals. 

An  abundant  ore  in  the  United  States.  Extensive  beds 
exist  in  Salisbury  and  Kent,  Ct.;  in  Beekman,  Fishkill, 
Dover,  Amenia,  S".  Y. ;  in  a  similar  situation  in  Richmond 
and  West  Stockbridge,  Mass.;  in  Bennington,  Monkton, 
>  Pittsford,  Putney,  and  Ripton,  Vt. ;  in  Pennsylvania,  the 
Carolinas,  Virginia,  and  the  region  south  westward  ;  also  in 
Missouri,  Iowa,  Wisconsin,  etc. 

This  is  one  of  the  most  valuable  ores  of  iron.  The  limo- 
nite  of  Western  New  England,  and  that  along  the  same 
range  geologically  in  Dutchess  Co.,  New  York,  Eastern 
Pennsylvania,  and  beyond  is  remarkably  free  from  phos- 
phorus, and  hence  is  highly  valued  for  its  iron.  Bog  ores 
usually  contain  much  phosphorus,  from  organic  sources, 
and  hence  the  iron  afforded  is  best  fitted  for  castings.  Li- 
monite  is  also  pulverized  and  used  for  polishing  metallic 
buttons  and  other  articles.  As  yellow  ochre,  it  is  a  common 
material  for  paint. 

Gothite  (Pyrrhofriderite,  Lepidokrokite).  An  iron  hydrate,  often  in 
fine  prismatic  crystals,  as  well  as  fibrous  and  massive  ;  G.  =  4'0-4'4  ; 
streak  brownish  yellow  ;  Feq4Ha(=  FeO3  +  H2O). 

Turgite.  Resembles  limonite,  but  gives  a  reddish  powder,  and  has 
the  formula  FeO7H2  =  2£eO3  -f H2O  ;  G.  =414.  It  occurs  with 
limonite  at  the  ore  beds  of  Salisbury,  Ct.,  and  others  in  the  same 
range.  Xanthosiderite  and  Limnite  are  other  related  hydrates. 

Melanosiderite.  Hydrous  iron  sesquioxide,  with  7 '42  of  silica  ; 
gelatinizes  ;  lustre  vitreous  ;  fusible.  From  Mineral  Hill,  Pa. 

SULPHATES,  BOKATE,  TUNGSTATE,  NIOBATES,  TANTALATES. 
Melanterite. — Copperas.     Iron  Vitriol.     Green  Vitriol. 

Monoclinic ;  in  acute  oblique  rhombic  prisms.  Cleavage 
basal,  perfect.  Generally  pulverulent  or  massive. 


200  DESCRIPTIONS   OF  MINERALS. 

Color  greenish  to  white.  Lustre  vitreous.  Subtranspa- 
rent  to  translucent.  Taste  astringent  and  metallic.  Brittle. 
H.  =2.  G.  =1-83. 

Composition.  Fe04S  -f  7aq  (or  FeO  +  S03  -f  7aq)  =  Sul- 
phur trioxide  28  8,  iron  protoxide  25 '9,  water  45*3  =  100. 
B.B.  becomes  magnetic.  Yields  glass  with  borax.  On  ex- 
posure, becomes  covered  with  a  yellowish  powder. 

Obs.  This  species  is  the  result  of  the  decomposition  of 
pyrite,  marcasite  and  pyrrhotite,  which  readily  afford  it  if 
moistened  while  exposed  to  the  atmosphere,  and  it  is  obtained 
from  these  sulphides  for  the  arts  (p.  191).  An  old  mine 
near  Goslar,  in  the  Hartz,  is  a  noted  locality.  The  variety 
Luckite  contains  some  manganese  ;  from  Utah,  Lucky  Boy 
mine. 

Copperas  is  much  used  by  dyers  and  tanners,  on  account 
of  its  giving  a  black  color  with  tannic  acid,  an  ingredient 
in  nutgalls  and  many  kinds  of  bark.  For  the  same  reason, 
it  forms  the  basis  of  ordinary  ink,  which  is  essentially  an 
infusion  of  nutgalls  and  copperas.  It  is  also  employed  in 
the  manufacture  of  Prussian  blue.  In  the  United  States 
the  amount  made  in  1884  was  about  fifteen  million  pounds, 
but  none  of  it  from  U.  S.  iron  sulphides. 

Coguimbi/e,  Gopiapite,  Voltaite,  Raimondite,  Botryogen,  Fibroferrite, 
Utahite,  Ihleife,  Clinophceite,  Clinochrocile ,  are  names  of  other  hydrous 
iron  sulphates  ;  and  HalotricMte  is  an  iron-alum.  Utahite  is  from  the 
Tintic  dist.,  Utah. 

Jarosite.  Hydrous  iron -potassium  sulphate.  Spain;  Chaffee  Co., 
Col. 

Sideronatrite.  Hydrous  iron-sodium  sulphate ;  insoluble.  Peru. 
Urusite  is  the  same  ;  Caspian  Sea. 

Pisanite.     Iron-copper  vitriol.     Tuscany  ;  Turkey. 

Lagonite.     Hydrous  iron  borate.    From  the  Tuscan  lagoons. 

Wolframite. — Wolfram.     Iron-manganese  Tungstate. 

M'onoclinic.  Also  massive.  Color  dark  grayish  black. 
Streak  dark  reddish  brown.  Lustre  submetallic,  shining, 
or  dull.  H.  =  5-5-5.  G.  =  7 '1-7 '5. 

Composition.  (Fe,Mn)04W  (or  (Fe,Mn)0  -f  W03).  A 
typical  variety  affords  tungsten  trioxide  76 '47,  iron  prot- 
oxide 9 '49,  manganese  protoxide  14-04  =  100.  B.B.  fuses 
easily  to  a  magnetic  globule ;  with  aqua  regia  dissolved 
with  the  separation  of  yellow  tungsten  trioxide.  Hubnerite 
is  a  manganese  wolframite,  containing  no  iron  ;  and  Fer- 
lerite  is  an  iron  wolframite. 


IRON. 


201 


Found  often  with  tin  ores.  Occurs  in  Cornwall;  at 
Zinnwald  and  elsewhere.  In  the  U.  States,  at  Monroe  and 
Trumbull,  Ct.;  on  Camdage  Farm,  near  Blue  Hill  Bay, 
Me. ;  near  Mine  La  Motte,  Mo. ;  at  the  Flowe  Mine,  N.  C. ; 
in  Mammoth  Mining  district,  Ney.  (Hubnerite)',  the  same 
in  Ouray  Co.,  Col.,  and  in  Montana. 

The  metal  tungsten  is  employed  to  some  extent  in  making  "with 
iron  a  kind  of  steel  harder  than  ordinary  steel.  Soluble  tungstates  also 
have  some  uses  in  the  arts. 

Reinite.    Like  wolframite  in  composition,  but  tetragonal. 

Columbite. 

Orthorhombic ;  I /\  I  over  ?'-£  =  100°  40',  I/\i-l=; 
140°  20'.  In  rectangular  prisms,  more  or  less  modified. 
Also  massive.  Cleavage  parallel  to 
the  lateral  faces  of  the  prism,  some- 
what distinct. 

Color  iron-black,  brownish  black  ; 
often  with  a  characteristic  iridescence 
on  a  surface  of  fracture.  Streak  dark 
brown,  slightly  reddish.  Lustre  sub- 
motallic,  shining.  Opaque.  Brittle. 
H.  =  5-6.  G.  =  5  -4^6  -5 ;  also  6-6  '85 
when  containing  tantalum. 

Composition.    Iron  niobate,  of  the 

formula  Fe06Nb2  (or  (R,Mn)0  +  Nb20B)  =  Niobium  pen- 
toxide  79*6,  iron  protoxide  16*4,  manganese  protoxide  4*4, 
tin  oxide  0-5,  lead  and  copper  oxides  0*1  =  100.  Tantalum 
often  replaces  part  of  the  niobium.  B.B.  alone  infusi- 
ble. Imparts  to  the  borax  bead  the  yellow  color  due  to 
iron. 

Diff.  Its  dark  color,  submetallic  lustre,  and  a  slight  iri- 
descence, together  with  its  breaking  readily  into  angular 
fragments,  will  generally  distinguish  this  species  from  the 
ores  it  resembles. 

Obs.  In  granite  at  Bodenmais,  Bavaria;  in  Bohemia;  in 
the  U.  States,  in  granitic  veins,  at  Middletown,  Haddam, 
and  Branchville,  Ct. ;  Chesterfield,  Beverly,  and  Northfield, 
Mass.;  Acworth,  N.  H.;  Greenfield,  1ST.  Y.;  Standish,  Me.; 
in  granite  veins  in  Amelia  Co. .  Va. ;  at  Pike's  Peak,  Col. ; 
Black  Hills,  Dak.  A  crystal  from  Middletown  originally 
weighed  14  pounds  avoirdupois;  a  single  mass  occurred  in 
the  Black  Hills  weighing  a  ton  (W.  P.  Blake). 


202  DESCRIPTIONS   OF   MINERALS. 

This  mineral  was  first  made  known  from  American  speci- 
mens by  Mr.  Hatchett,  an  English  chemist,  and  the  new 
metal  it  was  found  to  contain  was  named  by  him  columbium. 

Tantaliie.  Fe(Mn)O6Ta2;  with  sometimes  tin  and  tungsten.  Allied 
to  columbite;  H.  =  6-6*5;  G.  =  7-8;  being  distinguished  by  its  high 
specific  gravity.  Finland;  Sweden;  near  Limoges  in  France; 
N.  Carolina;  Alabama.  The  Northfield  and  Branch ville  columbites 
are  nearly  tantalite  in  composition,  and  that  of  the  Black  Hills  is 
probably  the  same  species.  Mangantantalite  contains  more  manganese 
than  iron. 

Note. — The  metal  named  ColumMum  by  Hatchett  is  the  same  that 
was  later  called  Niobium,  without  any  good  reason  for  the  change  of 
name. 

PHOSPHATES,  ARSENATES. 
Vivianite. — Hydrous  Iron  Phosphate. 

Monoclinic.  In  modified  oblique  prisms,  with  cleavage 
in  one  direction  highly  perfect.  Also  radiated,  reniform, 
and  globular,  or  as  coatings. 

Color  deep  blue  to  green  and  white.  Crystals  usually 
green  at  right  angles  with  the  vertical  axis,  and  blue  paral- 
lel to  it.  Streak  bluish.  Lustre  pearly  to  vitreous.  Trans- 
parent to  translucent;  opaque  on  exposure.  Thin  laminae 
flexible.  H.  =  1-5-2.  G.  =  2'58-2*68. 

Composition.  Fe308P2  -f  8  aq  (or  3FeO  -f-  P205  -f  8  aq) 
=  Phosphorus  pentoxide  28 '3,  iron  protoxide  43 '0,  water 
28 '7  =  100.  B.B.  fuses  easily  to  a  magnetic  globule,  color- 
ing the  flame  greenish  blue.  Affords  water  in  a  glass  tube, 
and  dissolves  in  hydrochloric  acid.  Changes  by  oxidation 
of  the  iron. 

Diff.  The  deep-blue  color  and  the  little  hardness  are 
decisive  characteristics.  The  blowpipe  affords  confirmatory 
tests. 

Obs.  Found  with  iron,  copper  and  tin  ores,  and  some- 
times in  clay,  or  with  bog  iron  ore.  St.  Agnes  in  Cornwall, 
Bodenmais,  and  the  gold-mines  of  Vorospatak  in  Transyl- 
vania, afford  fine  crystallizations.  In  the  II.  States,  in 
crystals  at  Imlaystown,  N.  J. ;  at  Allentown,  in  Monmouth 
Co.,  Mullica  Hill,  in  Gloucester  Co.,  N.  J.  Often  fills  the 
interior  of  certain  fossils.  Also  at  Harlem,  N.  Y. ;  in 
Somerset  and  Worcester  Cos.,  Md. ;  with  bog  ore  in  Stafford 
Co.,  Va.  Abundant  at  Vaudreuil,  Canada,  with  limonite. 
The  blue  iron  earth  is  an  earthy  variety,  containing  about 
30  p.  c.  of  phosphoric  acid. 


IRON.  203 

Ludlamite.  In  monoclinic  crystals;  clear  green;  hydrous  phosphate 
of  iron.  Cornwall.  Koninckite  is  another,  from  Belgium. 

Dufrenite.  A  hydrous  phosphate  of  iron  sesquioxide;  color  dull 
green;  often  in  radiated  forms.  Destinegite  is  related  to  it;  Picite  also. 

Cacoxenite.  In  radiated  silky  tufts;  color  yellow  or  yellowish 
brown;  H.  —3-4;  G.  =  3 '38;  phosphate  of  iron  sesquioxide;  often 
contains  alumina.  Differs  from  wavellite,  which  it  resembles,  in  its 
yellower  color  and  iron  reactions.  Also  resembles  carphplite,  but 
has  a  deeper  color,  and  does  not  give  the  manganese  reactions.  On 
limonite  in  Bohemia. 

Chalcosiderite  and  Andrewsite  are  other  iron  phosphates. 

Richellite.  Supposed  to  be  an  iron-calcium  fluo-phosphate;  G.  =  2  ; 
cream-yellow.  Richelle,  Belgium. 

Strengite.  Hydrous  iron  phosphate,  related  in  formula  to  scoro- 
dite;  orthorhombic;  reddish.  Near  Giessen,  Germany. 

Triphylile.     An  iron  manganese-lithium  phosphate.     See  p.  208. 

Pharmacosiderite,  or  Cube  ore.  In  cubes;  dark  green  to  brown  and 
red;  lustre  adamantine,  not  very  distinct;  streak  greenish,  brownish; 
H.  =  2'5;  G.  =  3.  A  hydrous  arsenate  of  iron  sesquioxide,  contain- 
ing 43  per  cent,  of  arsenic  pentoxide.  Cornwall;  France;  Saxony; 
Hungary. 

Soorodite.  Orthorhombic;  pale  leek-green  or  liver-brown;  vitreous 
to  subadamantine  ;  subtransparent  to  nearly  opaque ;  H.  =  3*5-4; 
G.  =  3'l-3"3;  a  hydrous  arsenate  of  iron  sesquioxide.  Saxony; 
Carinthia;  Cornwall;  Brazil;  and  minute  crystals  near  Edenville, 
N.  Y.,  with  arsenical  pyrites.  Named  from  the  Greek  skorodon, 
garlic,  alluding  to  the  odor  B.B.  Iron  sinter  is  an  amorphous  fonn 
of  the  same. 

Arseniosiderite  is  another  iron  arsenate. 

Emmonsite.  Monoclinic?;  yellowish  green;  G.  about  5;  probably 
tellurite  of  iron.  Near  Tombstone,  Arizona. 

CARBONATES. 
Siderite.— Spathic  Iron.     Iron  Carbonate.     Chalybite. 


Rhombohedral ;  ^#  =  107°.  Cleavage  parallel  to 
R  easy.  Faces  often  curved.  Usually  massive,  with  a 
foliated  structure,  somewhat  curving.  Some- 
times in  globular  concretions  or  implanted 
globules. 

Color  grayish  white  to  brown ;   often  dark 
brownish  red.     Becomes  nearly  black  on  ex- 
posure.    Streak  uncolored.    Lustre  pearly     Translucent  to 
nearly  opaque.     H.  =  3-4-5.     G.  =  3 '7-3 -9. 

Composition.  Fe03C  (or  FeO  -f  CO,)  =  Carbon  dioxide 
37*9,  iron  protoxide  62-1  =  100.  Often  contains  some 
manganese  oxide  or  magnesia,  and  lime  replacing  part  of 
the  iron  protoxide.  B.  B.  it  blackens  and  becomes  magnetic; 


204  DESCRIPTIONS   OF  MINERALS. 

but  alone  it  is  infusible.  Dissolves  in  heated  hydrochloric 
acid  with  effervescence.  The  iron,  on  exposure  to  the  air, 
passes  to  the  sesquioxide  state,  and  usually  to  the  hydrous 
iron  sesquioxide  (limonite),  giving  the  siderite  a  brown  or 
brownish  yellow  color. 

The  ordinary  crystallized  or  foliated  variety  is  called 
spathic  or  sparry  iron,  because  the  mineral  has  the  aspect 
of  a  spar.  The  globular  concretions  found  in  some  amygda- 
loidal  rocks  have  been  called  spherosiderite  because  of  its 
spheroidal  forms.  An  argillaceous  variety  occurring  in  nod- 
ular forms  is  often  called  clay  iron  stone,  and  is  abundant 
in  coal  measures. 

Diff.  Cleavage  as  in  calcite  and  dolomite,  but  specific 
gravity  higher.  B.B.  readily  becomes  magnetic. 

Obs.  Occurs  in  rocks  of  various  ages,  and  often  accom- 
panies other  ores.  Large  deposits  and  veins  exist  in  gneiss 
and  mica  schist,  clay  slate ;  also  in  some  limestone ;  in  the 
Coal  formation  principally  in  the  form  of  clay  iron-stone. 
In  Styria  and  Carinthia,  abundant  in  gneiss  ;  in  the  Hartz, 
in  graywacke.  Cornwall,  Alstonmoor,  and  Devonshire  are 
English  localities. 

In  a  vein  in  gneiss  at  Eoxbury,  Ct. ;  occurs  also  at  Plym- 
outh, Vt.;  Sterling,  Mass.;  in  Antwerp,  Jefferson  Co., 
and  Hermon,  St.  Lawrence  Co.,  N.  Y.;  in  large  masses  in 
and  beneath  the  limonite  of  Salisbury,  Ct.;  Amenia,  1ST.  Y.; 
W.  Stockbridge,  Mass. ;  being,  it  is  supposed,  part  of  the  un- 
derlying limestone;  abundant  in  a  bed  of  limestone  south  of 
Hudson,  N.  Y.,  and  now  worked.  Clay  iron-stone  is  abun- 
dant in  the  coal  regions  of  Pennsylvania  and  other  coal- 
bearing  States. 

This  ore  is  employed  extensively  for  the  manufacture  of 
iron  and  steel. 

Mesitite  is  an  iron-magnesium  carbonate. 

Ankerite  is  like  rnesitite,  but  contains  in  addition  a  large  percentage 
of  calcium.  Both  make  parts  of  many  dolomitic  limestones,  and  are 
the  occasion  of  their  becoming  rusty  and  decomposed,  producing 
limonite. 

Humboldtine.    A  hydrous  iron  oxalate. 

General  Remarks.—  The  metal  iron  has  been  known  from  the  most 
remote  historical  period,  but  was  little  used  until  the  last  centuries  be- 
fore the  Christian  era.  Bronze,  an  alloy  of  copper  and  tin,  was  the 
almost  universal  substitute,  for  cutting  instruments  as  well  as  weapons 
of  war,  among  the  ancient  Egyptians  and  earlier  Greeks  ;  and  even 
among  the  Romans  (as  proved  by  the  relics  from  Pompeii),  and  also 


IRON.  205 

throughout  Europe,  it  continued  long  to  be  extensively  employed  for 
these  purposes. 

The  Chalybcs,  bordering  on  the  Black  Sea,  were  workers  in  iron  and 
steel  at  an  early  period  ;  and  near  the  year  500  B.C.,  this  metal  was 
introduced  from  that  region  into  Greece,  so  as  to  become  common  for 
weapons  of  war.  From  this  source  we  have  the  expression  chalybeate 
applied  to  certain  substances  or  waters  containing  iron. 

The  iron-mines  of  Spain  have  also  been  known  from  a  remote  epoch, 
and  it  is  supposed  that  they  have  been  worked  "at  least  ever  since 
the  times  of  the  later  Jewish  kings  ;  first  by  the  Tyrians,  next  by  the 
Carthaginians,  then  by  the  Romans,  and  lastly  by  the  natives  of  the 
country."  These  mines  are  mostly  contained  in  the  present  provinces 
of  New  Castile  and  Aragon.  Elba  was  another  region  of  ancient 
works,  "  inexhaustible  in  its  iron,"  as  Pliny  states,  who  enters  some- 
what fully  into  the  modes  of  manufacture.  The  mines  are  said  to 
have  yielded  iron  since  the  time  of  Alexander  of  Macedon.  The  ore 
beds  of  Styria,  in  Lower  Austria,  were  also  a  source  of  iron  to  the 
Romans. 

The  ores  from  which  the  iron  of  commerce  is  obtained  are  the  sider- 
ite  (spathic  iron),  magnetite  (magnetic  iron),  hematite  (specular  iron), 
limonitc  ("  brown  hematite"),  and  bog  iron  ore.  In  England,  the  prin- 
cipal ore  used  is  an  argillaceous  carbonate  of  iron,  called  often  clay 
iron  stone,  found  in  nodules  and  layers  in  the  coal  measures.  It  con- 
sists of  carbonate  of  iron,  with  some  clay,  and  externally  has  an  earthy, 
stony  look,  with  little  indication  of  the  iron  it  contains  except  in  its 
weight.  It  yields  from  20  to  35  per  cent,  of  cast  iron.  The  coal  basin 
of  South  Wales,  and  the  counties  of  Stafford,  Salop,  York,  and  Derby, 
yield  by  far  the  greater  part  of  the  English  iron.  Brown  hematite  is 
also  extensively  worked.  In  Sweden  and  Norway,  at  the  famous 
works  of  Dannemora  and  Arendal,  the  ore  is  the  magnetic  iron  ore, 
and  is  nearly  free  from  impurities  as  it  is  quarried  out.  It  yields  50  to 
60  per  cent,  of  iron.  The  same  ore  is  worked  in  Russia,  where  it 
abounds  in  the  Urals.  The  Elba  ore  is  the  specular  iron  or  hematite. 
In  Germany,  Styria,  and  Carinthia,  extensive  beds  of  spathic  i;on  are 
worked.  The  bog  ore  is  largely  reduced  in  Prussia. 

In  the  United  States  all  these  different  ores  are  worked.  The  local- 
ities are  already  mentioned.  The  magnetic  ore  is  reduced  in  New 
England,  New  York,  Northern  New  Jersey,  and  sparingly  in  Pennsyl- 
vania, and  other  States.  Limonite,  or  brown  hematite,  is  largely 
worked  along  Western  New  England  and  Eastern  New  York,  in  Penn- 
sylvania, and  many  States  South  and  West.  The  earthy  argillaceous 
carbonate  like  that  of  England,  and  the  hydrate,  are  found  with  the 
coal  deposits,  and  are  a  source  of  much  iron. 

The  number  of  tons  (2240  Ibs.)  of  iron  manufactured  in  the  world 
in  the  year  1882  was  about  21,000,000,  of  which  Great  Britain  pro- 
duced 8,500,000  tons,  U.  States  4,623,000  tons,  Germany  3,171,000  tons, 
France  2,033,000  tons,  Belgium  717,000  tons,  Austria  with  Hungary 
525,000  tons,  Russia  450,000  tons,  Sweden  440,000  tons,  other  coun- 
tries  210,000.  In  1860  the  number  of  tons  produced  in  the  U.  States 
was  less  than  900,000;  in  1883,  about  4,600,000;  in  1884,  4,100,000. 


206  DESCRIPTIONS   OF   MINERALS. 


MANGANESE. 

The  common  ores  of  manganese  are  the  oxides,  the  car- 
bonate, and  the  silicates.  There  are  also  sulphides,  an  ar- 
senide, and  phosphates.  Specific  gravity  not  over  5  -2. 

\  SULPHIDES  AND  ARSENIDES. 

Aldbandite  or  Manganblende.  A  manganese  sulphide,  MnS  ;  iron 
black  ;  streak  green  ;  lustre  submetallic  ;  H.  =  3'5-4  ;  G.  =  3'9-4'0  ; 
crystals,  cubes,  and  regular  octahedrons.  Gold-mines  of  Nagyag, 
Transylvania  ;  Morocpcha,  Peru;  Summit  Co.,  Col. 

Hauerite.  A  sulphide,  MnS2;  reddish  brown,  brownish  black,  re- 
sembling blende  ;  H.  =  4  ;  G.  —  3 '46.  Hungary. 

Kawite.  Manganese  arsenide  ;  grayish  white  ;  metallic  ;  B.B.  gives 
off  alliaceous  fumes  ;  G.  =  5 -55.  Saxony. 

Manganostibiite  contains  both  arsenic  and  antimony.     Sweden. 

OXIDES. 
Manganosite. 

Isometric  crystals  ;  cleavage  cubic.  Emerald  green,  but 
brown  after  exposure.  Lustre  vitreous.  H.  =  5-6.  G.  = 
5.18. 

Composition.  MnO,  or  manganese  protoxide.  From 
Longban  and  Nordmark,  Sweden. 

V     Pyrolusite. — Manganese  Dioxide.     Black  Oxide  of  Manganese. 

Orthorhombic ;  /A  /=93°  40'.  In  small  rectangular 
prisms,  more  or  less  modified.  Some- 
times fibrous  and  radiated  or  diver- 
gent. Often  massive  and  in  reniform 
coatings.  Color  iron-black.  Streak 
black,  non-metallic.  H.  =  2-2  '5. 
G.  =  4-8. 

Composition.     Mn02  =  Manganese 
63-2,  oxygen  36 -8  =  100.    With  a  mi- 
nute portion,  borax  bead  deep  amethys- 
tine while  hot,  red-brown  on  cooling.     Yields  no  water  in 
a  matrass. 

Diff.  Differs  from  iron  ores  by  the  violet  glass  with 
borax. 

Obs.  Extensively  worked  in  Thuringia,  Moravia,  and 
Prussia.  Common  in  Devonshire  and  Somersetshire  in 


MANGANESE.  207 

England,  and  in  Aberdeenshire.  In  the  United  States, 
associated  with  the  following  species  at  Bennington,  Bran- 
don, Monkton,*Chittenden,  and  Irasburg,  Vt. ;  occurs  also 
at  Con  way,  Plainiield,  and  Richmond,  Mass. ;  in  Salisbury 
and  Kent,  Ct.;  the  Etowah  region,  Barton  Co.,  Ga.;  Au- 
gusta, Nelson,  Rockingham,  and  Campbell  Cos.,  Va. ;  the 
Crimora  mine  in  Augusta  Co.,  one  of  the  best  in  the  United 
States;  on  Red  Island,  in  the  Bay  of  San  Francisco;  at 
Pictou  and  Walton,  N.  Scotia;  near  Bathurst,  in  N. 
Brunswick. 

Named  pyrolusite  from  the  Greek  pur,  fire,  and  luoy  to 
^wash,  alluding  to  its  property  of  discharging  the  brown  and 
*  green  tints  of  glass. 

Hausmannite.  A  manganese  oxide,  2MnO  +  MnO2,  yielding  72'1 
per  cent,  of  manganese,  when  pure  ;  brownish  black ;  submetallic; 
massive  and  in  tetragonal  octahedrons;  H.  =  5-5-5;  G.  =  4'7.  Thu- 
ringia ;  Alsatia. 

Hetwrolite.     A  zinc-hausmannite.     Sterling  Hill,  N.  J. 

Braunite.  A  manganese  oxide  containing  69  per  cent,  of  manganese 
when  pure;  color  and  streak  dark  brownish  black;  lustre  submetallic; 
tetragonal  octahedrons  and  massive  ;  H.  =  6-6 '5  ;.  G.  =  4*8.  Pied- 
mont; Thuringia. 

Manganite.  A  hydrous  manganese  sesquioxide ;  massive  and  in 
rhombic  prisms;  steel-black  to  iron  black;  H.  =  4-4'5;  G.  =  4'3-4'4. 
The  Hartz ;  Bohemia ;  Saxony;  Aberdeenshire;  at  several  points  in 
New  Brunswick  and  Nova  Scotia. 

Crednerite.    Cupreous  manganese  oxide. 

Psilomelane. 

Massive  and  botryoidal.  Color  black  or  greenish  black. 
Streak  reddish  or  brownish  black,  shining.  H.  =  5-6. 
G.  =  4-4*4. 

Composition.  Essentially  manganese  dioxide  with  a  little 
water,  and  some  baryta  or  potassa;  of  varying  constitution. 
B.B.  like  pyrolusite,  except  that  it  aifords  water.  Lithio- 
phorite  is  a  lithia-bearing  variety. 

Obs.  An  abundant  ore,  associated  usually  with  pyrolusite; 
the  two  often  in  alternating  layers;  has  been  considered 
impure  pyrolusite.  Named  from  the  Greek  psilos,  smooth 
or  .naked,  and  melas,  black. 

Pyrochroite.  Hydrous  manganese  protoxide,  of  white  color; 
MnO2H2.  Sweden. 

Pdagite.  The  brownish  black  concretionary  manganese  nodules 
found 'in  many  regions  over  the  bottom  of  the  ocean;  affords,  accord - 
iag  to  an  analysis,  about  40  per  cent,  of  MnO2,  27  FeO3,  13  of  water 


208  •        DESCRIPTIONS   OF  MINERALS. 

lost  at  a  red  heat,  along  with  14  per  cent,  of  silica  and  4  of  alumina ; 
24-5  per  cent,  of  water  lost  below  100°  C.    Probably  a  mixture. 

Chalcophanile.  A  hydrous  manganese  zinc  oxide  in  rhomboheclral 
crystals  and  stalactites.  Sterling  Hill,  Sussex  Co.,  N.  J. 

Wad. — Bog  Manganese. 

Massive,  reniform,  earthy;  in  coatings  and  dendritic 
delineations.  Color  and  streak  black  or  brownish  black. 
Lustre  dull,  earthy.  H.  =  1-6.  G.  =  3-4.  Soils  the 
fingers. 

Composition.  Manganese  dioxide,  in  varying  proportions, 
from  30  to  70  per  cent.,  mechanically  mixed  with  more  or 
less  of  iron  sesquioxide,  and  10  to  25  per  cent,  of  water. 
Often  several  p.  c.  of  cobalt  oxide  present  (var.  Asbolite); 
and  sometimes  4-18  p.  c.  of  copper  oxide  (Lampadite).  It 
is  formed  in  low  places  from  the  decomposition  of  minerals 
containing  manganese.  Gives  off  much  water  when  heated, 
and  affords  a  violet  glass  with  borax. 

Obts.  Wad  occurs  in  Columbia  and  Dutchess  counties, 
N.  Y. ;  at  Blue  Hill  Bay,  Dover,  Me. ;  at  Nelson,  Gilman- 
ton,  and  Graf  ton,  N.  H.;  and  in  many  other  parts  of  the 
country. 

It  may  be  employed  like  the  preceding  in  bleaching,  but 
is  too  impure  to  afford  good  oxygen.  It  may  also  be  used 
for  umber  paint. 

SULPHATES. 
Mallardite. 

Fine,  fibrous.     Color  white.     Easily  soluble. 

Composition.  Hydrous  manganese  sulphate,  Mn04S  + 
7  aq  (or  MnO  +  S03  +  7  aq). 

Obs.  From  the  Silver  Mine  Lucky  Boy,  Butterfield 
Canon,  Utah. 

Szmikite.  Another  hydrous  sulphate  with  less  water.  Transyl- 
vania. 

Ilesite.  Hydrous  manganese  zinc-iron  sulphate  ;  white  ;  soluble. 
Hall  Valley,  Col. 

PHOSPHATES,  ARSENATES. 
Triphylite. 

Orthorhombic.  In  rhombic  crystals,  massive.  Color 
greenish  gray  to  bluish  gray,  but  often  brownish  black  ex- 


MANGANESE.  209 

ternally  from  the  oxidation  of  the  manganese  present. 
Streak  grayish  white.  Lustre  subresinous.  H.  =  5.  G.  = 
3-54-3-6. 

Composition.  A  hydrous  phosphate  of  iron,  manganese 
and  lithium,  (iLi2|R)308P2,  in  which  R  stands  for  Fe  and 
Mn.  A  Bodenmais  specimen  afforded  Phosphorus  pen- 
toxide  44-19,  iron  protoxide  3 8 -21,  manganese  protoxide 
5-63,  magnesia  2-39,  lime  0-76,  lithia  7 '69,  soda  0*74,  pot- 
ash 0-04,  silica  0-40  =  100-05.  B.B.  fuses  very  easily, 
coloring  the  flame  red,  in  streaks,  with  a  pale  bluish  green 
on  the  exterior  of  the  flame.  Soluble  in  hydrochloric  acid. 

Obs.  Found  at  Rabenstein  in  Bavaria ;  in  Finland ;  at 
Norwich,  Mass.;  Grafton,  JS".  H. 

Liihwphilite.  A  salmon-colored  manganese-lithium  phosphate,  al- 
lied in  composition  to  triphylite,  but  containing  very  little  iron. 
From  Branchville,  Ct. 

Fairfieldite.  Hydrous  manganese-calcium  phosphate  ;  triclinic  ; 
white,  yellowish;  B.B.  fuses  with  difficulty.  From  Branchville,  Ct.; 
also  Bavaria. 

Leucomanganite.  Snow-white,  but  contains  manganese,  iron,  alka- 
lies, and  water.  Rabenstein.  Probably  fairfieldite. 

Triplite. 

Orthorhombic;  I /\I  —  120°  54'.  Usually  massive;  cleav- 
age in  three  directions.  Color  blackish  brown.  Streak 
yellowish  gray.  Lustre  resinous.  Nearly  or  quite  opaque. 
H.  =  5-5-5.  G.  =3-4-3-8. 

Composition.  (Mn,Fe)a08P2  +  RF2  (or  3(Mn,Fe)0  + 
P205  -f-  RF2),  affording  about  30  per  cent,  of  manganese 
protoxide,  8  of  fluorine.  Fuses  easily  to  a  black  magnetic 

S^obule.    B.B.  imparts  a  violet  color  to  the  hot  borax  bead, 
issolves  in  hydrochloric  acid. 

Obs.  From  Limoges  in  France;  Washington,  Ct.;  Ster- 
ling, Mass. 

Heterosite,  Alluaudite,  Pseudotriplite.  Regarded  as  results  of  altera- 
tion, either  of  triphyline  or  of  triplite. 

Talktriplite  is  a  triplite  containing  calcium  and  magnesium. 

Triploidite.  A  manganese  iron  phosphate,  like  triplite,  but  having 
the  fluorine  replaced  by  the  elements  of  water.  From  Branchville,  Ct. 

Dwkinsonite.  Oil-green  to  olive-green ;  manganese-iron-calcium 
phosphate.  From  Branchville,  Ct. 

lleddingite.  Rose-pink;  hydrous  manganese-iron  phosphate.  Mn8 
OePa  -f-3aq.,  isomorphous  with  scorodite.  Branchville,  Ct. 

Hureaulite.    Rose-colored  to  brownish  orange;  hydrous  manganese- 
iron  phosphate.     Bureaux,  France. 
14 


210  DESCRIPTIONS  OF  MINERALS. 

Mllowlte.  Manganese-iron-sodium  phosphate;  monoclinic;  yellow, 
brown.  From  Branchville,  Ct. 

ARSENATES  OP  MANGANESE.    Allaktite,  Diadelphite,  Hemqfibrite, 
Synadelphite,  Polyarsenite,  Sarkinite,  are  names  of  arsenates.     From 
weden. 

CARBONATES. 
Rhodochrosite. — Manganese  Carbonate. 

Rhombohedral;  R/\R=  106°  51';  like  calcite  in  having 
three  easy  cleavages,,  and  in  lustre.  Color  rose-red.  H.  = 
3-5-4-5.  G.  =3-4-3-7. 

Composition.  Mn03C  (or  MnO  -+-  C02)  —  Carbonic  acid 
38 '6,  manganese  protoxide  61-4  =  100.  Part  of  the  man- 
ganese often  replaced  by  calcium,  magnesium,  or  iron. 

Obs.  From  Saxony,  Transylvania,  the  Hartz,  Ireland ; 
Mine  Hill,  N.  J. ;  Branchville,  Ct.;  Austin,  Nev.;  Alice 
Mine,  Butte  City,  Montana;  Summit  Co.,  Col.;  Placentia 
Bay,  Newfoundland. 

Rhodonite,  Kentrolite,  Helvite.    Manganese  silicates.     See  p.  268. 

General  Remarks. — The  most  productive  localities  of  manganese  ore 
in  the  United  States  are  those  of  Augusta  Co.,  Va.,  and  Barton  Co  , 
Ga.  The  former  produced,  in  1885,  18,745  tons;  the  latter  2580; 
Arkansas  about  15GO,  and  other  States  about  500  tons.  It  is  imported 
from  Nova  Scotia  and  Spain. 

Manganese  is  never  employed  in  the  arts  in  the  pure  state.  In  the 
condition  of  ore,  especially  pyrolusite,  it  is  largely  employed  in  bleach- 
ing. The  importance  of  the  ore  for  this  purpose  depends  on  the 
oxygen  it  contains,  and  the  facility  with  which  this  gas  is  given  up. 
When  this  ore  is  treated  with  hydrochloric  acid,  the  chlorine  of  the 
acid  is  given  off  ;  and  by  receiving  this  gas  in  slaked  lime  "  bleach- 
ing powder"  is  made,  a  mixture  of  calcium  chloride  with  calcium 
hypochlorite.  The  ore  easily  gives  off  its  oxygen  when  highly  heated, 
and  its  use  in  discharging  the  green  and  brown  color  of  glass  (due  to 
iron)  depends  on  this.  The  binoxide  of  manganese,  when  pure, 
affords  18  parts  by  weight  of  chlorine  to  22  parts  of  the  oxide;  or  23 £ 
cubic  inches  of  gas  from  22  grains  of  the  oxide.  The  best  ore  should 
give  about  three  fourths  its  weight  of  chlorine,  or  about  7000  cubic 
inches  to  the  pound  avoirdupois. 

Iron  ores  containing  some  manganese  are  used  for  making  spiegel- 
eisen,  a  hard  highly  crystallized  pig-iron,  containing  10  to  15  p.  c.  of 
manganese  with  a  large  amount  of  carbon.  This  spiegeleisen  is  com- 
monly used  in  the  Bessemer  process  for  making  steel.  Manganese  is 
also  employed  to  give  a  violet  color  to  glass.  The  sulphate  and  the 
chloride  of  manganese  are  used  in  calico  printing.  The  sulphate 
gives  a  chocolate  or  bronze  color.  Manganese  borate  has  been  used 
to  give  the  drying  quality  to  varnishes. 


ALUMINIUM. 


ALUMINIUM. 

The  aluminium  compounds  among  minerals  include  a 
sesquioxide  A103,  hydrated  oxides,  fluorides,  sulphates, 
phosphates,  and  numerous  silicates.  There  are  no  sul- 
phides or  arsenides,  and  no  carbonate,  with  a  single  excep- 
tion. 

The  silicates  are  described  in  the  following  section.  Many 
infusible  aluminium  compounds  may  be  distinguished  by 
means  of  a  blowpipe  experiment,  as  explained  on  page  98. 

The  metal  aluminium  is  obtained  by  diiferent  methods 
from  alumina,  and  the  fluoride  (cryolite);  and  recently,  at 
Cleveland,  from  corundum  easily  by  electric  heating;  reduc- 
ing the  price  to  five  dollars  a  pound,  or  a  third  of  the  previous 
cost  (Am.  J.  Sci.  xxx.,  308,  1885).  It  is  highly  useful 
in  alloys  with  copper  as  aluminium  bronze,  and  also  with 
iron  and  other  metals. 

OXIDES. 
Corundum. 

Rhombohedral ;  R  A  R=86°  4'.  Cleavage  sometimes 
perfect  parallel  to  0,  and  sometimes  parallel  to  R.  "Usual 
in  six-sided  prisms,  often  with  uneven  sur- 
faces, and  very  irregular.  Also  granular  mas- 
sive. Colors:  blue,  and  grayish  blue,  most 
common;  gray,  red,  yellow,  brown,  and  nearly 
black;  often  bright.  When  polished  on  the 
surface  O,  an  internal  star  of  six  rays  some- 
times distinct.  Transparent  to  translucent. 
H.  =  9,  or  next  below  the  diamond.  Ex- 
ceedingly tough  when  compact.  G.  =  4  when 
pure;  3 -94-4-16. 

Composition.  A103=  Oxygen  46 "8,  aluminium  53 '2  =  100; 
pure  alumina.  B.B.  unaltered  both  alone  and  with  soda. 
In  fine  powder  with  cobalt  nitrate  and  ignited,  becomes 
blue. 

VARIETIES.  The  name  sapphire  is  usually  restricted,  in 
common  language,  to  clear  crystals  of  bright  colors,  used  as 
gems ;  while  dull,  dingy-colored  crystals  and  masses  are 
called  corundum,  and  the  granular  variety  of  bluish  gray 
and  blackish  colors  containing  much  disseminated  magnetite 
(whence  its  dark  color)  is  called  emery. 


212  DESCRIPTIONS  OP  MINERALS. 

Blue  is  the  true  sapphire  color.  It  is  called  oriental  ruby, 
when  red;  oriental  topaz,  when  yellow;  oriental  emerald, 
when  green;  oriental  amethyst,  when  violet;  and  adaman- 
tine spar,  when  hair-brown.  Crystals  with  a  radiate  cha- 
toyant interior  are  very  often  beautiful,  and  are  called 
aster ia,  or  aster  iated  sapphire. 

Diff.  Distinguished  readily  by  its  great  hardness. 

Obs.  The  sapphire  is  often  found  loose  in  the  soil.  Meta- 
snorphic  rocks,  especially  gneissoid  mica  schist,  and  granu- 
lar limestone,  appear  to  be  its  usual  matrix.  It  is  met  with 
in  several  localities  in  the  United  States;  blue  at  Newton, 
]ST.  J.,  crystals  sometimes  several  inches  long,  also  at  Frank- 
lin and  Sparta;  bluish  and  pink  crystals  at  Warwick,  and 
white,  blue,  and  reddish  at  Amity,  N".  Y. ;  grayish,  in  large 
crystals,  in  Delaware  and  Chester  Cos.,  Pa.;  pale  blue  in 
bowlders  at  West  Farms  and  Litchfield,  Ct.  Abundant  at 
Corundum  Hill,  Macon  Co.,  N".  C.,  where  crystals  are  nu- 
merous, and  some  fit  for  jewelry,  and  where  one  has  been 
obtained  weighing  312  pounds,  having  a  reddish  color  out- 
side and  a  bluish-gray  within;  also  in  Jackson,  Burke, 
Heywood,  Madison,  and  Clay,  and  other  Cos.;  Laurens 
Dist.,  S.  C.;  Tallapoosa  Co.,  Ala.;  also  in  Fannin  Co.,  Ga.; 
Los  Angeles  Co.,  Cal.;  near  Helena,  Montana,  affording 
some  good  gems;  Santa  Fe,  N.  Mexico;  Arizona;  Colorado; 
emery,  formerly  mined,  at  Chester,  Mass. 

The  principal  foreign  localities  are  as  follows:  blue,  from 
Ceylon;  the  finest  red  from  the  Capelan  Mountains  in  the 
kingdom  of  Ava,  and  smaller  crystals  from  Saxony,  Bohemia, 
and  Auvergne;  corundum,  from  the  Carnatic,  on  the  Mala- 
bar coast,  and  elsewhere  in  the  East  Indies;  adamantine 
spar,  from  the  Malabar  coast;  emery,  in  large  bowlders,  from 
near  Smyrna,  and  also  at  Naxos  and  several  of  the  Grecian 
islands. 

The  name  sapphire  is  from  the  Greek  word  sapplieiroz,  the 
name  of  a  blue  gem.  It  is  doubted  whether  it  included  the 
sapphire  of  the  present  day. 

Next  to  the  diamond,  the  sapphire  in  some  of  its  varieties 
is  the  most  costly  of  gems.  The  red  sapphire  is  much  more 
highly  esteemed  than  those  of  other  colors;  a  crystal  of  one, 
two,  or  three  carats  has  the  value  of  a  diamond  of  the  same 
size.  They  seldom  exceed  half  an  inch  in  their  dimensions. 
Two  splendid  red  crystals,  as  long  as  the  little  finger  and 
about  an  inch  in  diameter,  are  said  to  be  in  the  possession 


ALUMINIUM.  213 

of  the  king  of  Arracan.  The  largest  oriental  ruby  known 
was  brought  from  China  to  Prince  Gargarin,  governor  of 
Siberia;  it  afterwards  came  into  the  possession  of  Prince 
Menzikoff,  and  constitutes  now  a  jewel  in  the  imperial 
crown  of  Russia.  Blue  sapphires  occur  of  much  larger 
size.  According  to  Allan,  Sir  Abram  Hume  possessed  a 
crystal  which  was  three  inches  long.  One  of  9  *51  carats  is 
stated  to  have  been  found  in  Ava. 

Corundum  and  emery  are  crushed  to  a  powder  of  differ- 
ent degrees  of  fineness,  and  make  the  abrading  and  polish- 
ing material  called  in  the  shops  emery.  The  iron  oxide  of 
true  emery  diminishes  its  hardness,  and  consequently  its 
abrasive  power;  pulverized  corundum  is  more  valuable  and 
efficient  in  abrasion. 


Diaspore.  Aluminium  hydrate,  AlO^H.,  (or  AlO3H2O)  =  Water  14  9, 
alumina  85'1  =  100;  crystals  usually  thin  plates;  alsoacicular;  whitish, 
grayish,  pinkish,  etc.;  brittle;  translucent;  H.  6'5-7;  G.  3'5.  The 
Urals;  Schemnitz;  Chester,  Mass.;  Unionville,  Chester  Co.,  Pa.,  some 
cryst.  1^  in.  long;  Culsagee  mine,  N.  C.  Usually  found  with  corun- 
dum. 

Gibbsite(IIydrargilUtt).  Aluminium  hydrate;  AlO6H6  =  Water  34*5, 
alumina  65'5  =  100.  In  hexagonal  crystals,  sometimes  transparent; 
commonly  in  whitish  stalactitic  and  mammillary  forms,  with  smooth 
surface,  looking  like  chalcedony;  H.=  2'5-3'5;  G.  =  2  '3-2  '4.  Near 
Slatoust  in  the  Ural;  Asia  Minor;  on  corundum  at  Unionville,  Pa.;  at 
Richmond,  Mass.,  stalactitic;  in  Dutchess  and  Orange  Cos.,  N.  Y. 
Zirlite  is  similar. 

HydrotaiciU  (Volknerite,  Houghite).  Soft  pearly;  contains  alumina, 
magnesia,  and  water.  A  result  of  the  alteration  of  spinel  crystals. 
Near  Slatoust;  Snarum,  Norway;  Oxbow,  Rossie,  St.  Lawrence  Co., 
N.  Y.  (var.  Houghite). 

Beauxite.  Aluminium-iron  hydrate;  in  concretionary  forms  and 
grains.  Beaux,  France,  etc. 

Spinel. 

Isometric.  In  octahedrons,  more  or  less  modified.  Fig- 
ure 3  represents  a  twin  crystal.  Occurs  only  in  crystals; 
cleavage  octahedral,  but  difficult. 

Color  red,  passing  into  blue,  green,  yellow,  brown,  and 
black.  The  rod  shades  often  transparent  and  bright;  the 
dark  shades  usually  opaque.  Lustre  vitreous.  H.  =  8. 
G.  =3-5-4-1. 

Composition.  MgA104  (or  MgO  +A10,)  =  Alumina  72, 
magnesia  28  =  100.  The  aluminium  is  sometimes  re- 
placed in  part  by  iron,  and  the  magnesium  often  in  part  by 


214 


DESCRIPTIONS   OF   MINERALS. 


iron,  calcium,  manganese,  and  zinc.     Infusible;  insoluble 
in  acids. 

VARIETIES.  The  scarlet  or  bright  red  crystals,  spinel 
ruby;  rose-red,  balas-ruby ;  orange-red,  rubicelle;  violet, 
almandine  ruby;  green,  '  cliloro-spintl ;  black,  pleonaste. 


3. 


Pleonaste  contains  sometimes  8  to  20  per  cent,  of  oxide  of 
iron.  Picotite  contains  iron  with  7  p.  c.  of  chromium 
oxide;  G.  =:  4-08. 

Diff.  The  form  of  the  crystals  and  their  hardness  dis- 
tinguish the  species.  Garnet  is  fusible.  Magnetite  is  at- 
tracted by  the  magnet.  Zircon  has  a  higher  specific  gravity. 
The  red  crystals  often  resemble  the  true  ruby  (red  corun- 
dum), but  the  latter  are  never  in  octahedrons. 

Obs.  Occurs  in  granular  limestone;  also  in  gneiss  and 
volcanic  rocks.  At  numerous  places  in  the  adjoining  coun- 
ties of  Sussex,  *N.  J.,  and  Orange  Co.,  N.  Y.,  of  various 
colors  from  red  to  brown  and  black;  especially  at  Vernon, 
Franklin,  Newton,  and  Hamburg,  in  the  former,  and  in 
Warwick,  Amity,  Monroe,  Norwich,  Cornwall,  and  Eden- 
ville  in  the  latter.  One  octahedron,  found  at  Amity  by 
Dr.  Heron,  weighed  49  pounds.  The  limestone  quarries 
of  Bolton,  Boxborough,  Chelmsford,  and  Littleton,  Mass., 
afford  a  few  crystals;  also  San  Luis  Obispo,  Gal.;  bluish, 
at  Wakefield,  Canada. 

Crystals  of  spinel  have  occasionally  undergone  a  change 
to  the  steatite-like  mineral  Uydrotalcite  (see  p.  213). 

Uses.  The  fine  colored  spinels  are  much  used  as  gems. 
The  red  is  the  common  ruby  of  jewelry,  the  oriental  rubies 
being  sapphire. 

Gahnite.  A  spinel  in  which  zinc  takes  the  place  of  part  or  all  of 
the  magnesium;  when  all,  it  is  called  Automolite ;  dark  green  or 
greenish  black  ;  H.  =  7'5-8  ;  G.  =  4-4'6;  fused  with  sufficient  soda, 
B.B.  on  coal,  a  white  coat  of  zinc  oxide,  which  is  yellow  when  hot ; 
B.B.  infusible.  Franklin,  N.  J.;  Rowe,  Mass.,  in  a  vein  of  pyrite; 


ALUMINIUM. 


Mitchell  Co.,  Deak  mine,  N.  C.;  Canton  mine,  Ga.;  Colorado  ;  New 
Mexico  ;  Sweden,  near  Fahlun,  in  talcose  slate. 

Dysluite.  A  gahnite  containing  manganese;  yellowish  or  grayish 
brown  ;  H.  =  7*5-8  ;  G.  —  4'55  ;  composition,  Alumina  30'5,  zinc 
oxide  16*8,  iron  sesquioxide  41 '9,  manganese  protoxide  7'6,  silica  3, 
water  0'4.  Sterling,  N.  J.,  with  franklinite  and  troostite. 

Kreittonite.     A  zinc-iron  gahnite;  G.  =  4'48-4'89. 

Hercynite.  A  spinel  affording  on  analysis  alumina  and  iron  pro- 
toxide, with  only  2  '9  per  cent,  of  magnesia  ;  G.  =  3 '9-3 '95. 

ChrysoberyL 

Orthorhombic ;  /A  /=129°  38'.  Also  in  compound 
crystals,  as  in  Fig.  2.  Crystals  sometimes  thick ;  often 
tabular. 

Color  bright  green,  from  light  to  emerald-green  and 
brown ;  rarely  raspberry-  or  columbine-red  by  transmitted 
light.  Streak  uncolored.  Lustre  vitreous.  Transparent 
to  translucent.  H.  =  8 -5.  G.  =  3 '7-3 '86. 

Composition.  BeA104  (or  BeOA10a)  =  Alumina  80*2, 
glucina  19-8  =  100.  B.B.  infusible  and  unaltered. 

Alexandrite,  from  the  Urals,  is  colored  emerald-green 
by  chrome;  bears  the  same  relation  to  ordinary  chryso- 
beryl  as  emerald  to  beryl.  Fig.  2  is  of  this  variety. 

Diff.  Near  beryl,  but  distinct  in  not  being  regularly  hex- 
agonal in  crystallization. 

Obs.  Chrysoberyl  occurs  in  the  United  States  in  granite 
at  Haddam,   Ct.    (loc.    not  accessible) ;    Greenfield,  near 
Saratoga,  N.  Y.;    Stow   (one  crystal  3x5x1  inches), 
Canton,  Peru,  Stoneham,  Norway,  Maine. 
1.  2. 


Named  from  the  Greek  chrysos,  golden,  fieri/Uos,  beryl. 

The  crystals  are  seldom  sufficiently  pellucid  and  clear 
from  flaws  to  be  valued  in  jewelry;  but  when  of  fine  qual- 
ity, it  forms  a  beautiful  gem,  and  is  often  opalescent. 


216  DESCRIPTION'S   OF  MINERALS. 

FLUORIDES  OP  ALUMINIUM. 
Cryolite. — Aluminium-Sodium  Fluoride.    Ice  Stone. 

Monoclinic  ;  I/\I '.=  88i°-88°.  Eectangular  cleavages. 
Usually  massive;  white.  Translucent.  G.  =  2 '9-3-1. 

Composition.  3NaF  -f  A1F3  —  Aluminium  13  -0,  sodium 
32*8,  fluorine  54 -2  =  100.  Fusible  in  the  name  of  a  candle, 
and  thus  easily  distinguished. 

Obs.  From  Greenland ;  sparingly,  Pike's  Peak  region, 
at  the  N.  E.  base  of  St.  Peter's  Dome.  Used  in  making 
soda,  porcelain-like  glass,  and  the  metal  aluminium. 
Another  cryolite-like  species,  Elpasolite,  occurs  at  Pike's 
Peak,  in  which  the  sodium  is  largely  replaced  by  potassium. 

Pachnolite.  Monoclinic ;  /  A  T=  81°  24';  white,  yellowish;  like 
cryolite  in  composition  except  that  half  the  sodium  is  replaced  by 
calcium,  and  water  is  present ;  formed  by  the  alteration  of  cryolite. 
Greenland;  Pike's  Peak,  Col. 

TJwmsenolite.  Like  pachnolite  in  composition;  monoclinic;  If\l 
near  90°;  cleavage  basal,  very  perfect;  Greenland;  Pike's  Peak. 

Oearkmktite.  Earthy,  kaolin  like;  hydrous,  like  the  last,  but  con- 
taining calcium  with  no  sodium.  Greenland;  Pike's  Peak.  Evigto- 
kite  is  probably  the  same. 

Arksuktite,  Chiolite,  Chodneffite  are  related  species,  the  latter  two 
from  Siberia. 

Balstonite.  In  minute  cubo-octahedrons;  a  hydrous  sodium- 
aluminium  fluoride.  Occurs  in  Greenland  cryolite ;  probably  with 
pachnolite  of  Pike's  Peak. 

Fluellite.  In  minute  white  rhombic  octahedrons;  contains  alumin- 
ium and  fluorine.  Cornwall. 

Prosopite.  Monoclinic;  white  or  grayish;  a  hydrous  aluminium- 
calcium  fluoride.  Altenberg;  cryolite  locality  of  Pike's  Peak. 

Chloraluminite.    A  hydrous  aluminium  chloride.    Vesuvius. 

SULPHATES,  BORATES. 
Alunogen. — Hydrous  Aluminium  Sulphate. 

In  silky  efflorescences  and  crusts  of  a  white  color,  hav- 
ing a  taste  like  common  alum.  H.  =  1-5-2.  G.  =  1  '6-1  -8. 

Composition.  A101QS3  -f  18aq.  (or  A103  -f  3S03  +  18aq. ) 
=  Sulphur  trioxide  36 '0,  alumina  15 -4,  water  48  •&  =  100. 

Obs.  Common  as  an  efflorescence  in  solfataras  of  volcanic 
regions,  and  also  often  occurring  in  shales  of  coal  regions 
and  other  rocks  containing  pyrite ;  the  oxidation  of  the 
iron  sulphide  affords  sulphuric  acid,  which  acid  combines 
with  the  alumina  of  the  shale. 


ALUMINIUM.  217 

Alums.  Frequently  the  sulphuric  acid  resulting  from  the  oxidation 
of  a  sulphide,  or  in  some  other  way,  combines  also  with  the  iron, 
magnesia  or  potash  or  soda  of  the  shale  or  other  rock,  as  well  as  the 
alumina,  and  so  makes  other  kinds  of  aluminium  sulphate. 

Combining  thus  with  potash,  it  produces  common  alum  called  Kali- 
nite  or  potash  alum,  whose  formula  is  K2Al3OQ4S4  -|-18aq.;  with  am- 
monia, it  forms  an  ammonia-alum,  named  Tschermigite ;  with  iron, 
iron-alum,  called  Halotrichite ;  with  soda,  soda-alum,  Mendozile  ; 
with  magnesia,  magnesia- alum,  Pickeringite;  with  manganese,  man- 
ganese alum,  Apjohnite  and  Bosjemanite.  The  formulas  of  these 
alums  are  alike  in  atomic  proportions,  excepting  in  the  amount  of. 
water,  which  varies  from  ISaq.  to  24aq. 

Sonomaite.  From  the  Geyser  region  of  Sonoma  Co.,  Cal.,  is  near 
pickeringite.  PlagiodtriU  is  soluble  aluminium-sodium-potassium- 
iron  sulphate.  Lmwigite  is  aluminium-potassium  sulphate,  containing 
half  the  water  of  pickeringite.  Dmnreicherite  is  a  magnesian  alum 
of  peculiar  composition.  Dietrichite  is  near  the  alums. 

•Shale  containing  alunogen  or  any  of  the  alums  is  often  called  alum- 
shale.  Rocks,  whether  shales  or  of  other  kinds,  are  often  quarried 
and  lixiviated  for  the  alum  they  contain  or  will  afford.  The  rock  is 
first  slowly  heated  after  piling  it  in  heaps,  in  order  to  decompose  the 
remaining  pyrites  and  transfer  the  sulphuric  acid  of  any  iron  sulphate 
to  the  alumina  and  thus  produce  the  largest  amount  possible  of  alu- 
minium sulphate.  It  is  next  lixiviated  in  stone  cisterns.  The  lye  con- 
taining this  sulphate  is  afterwards  concentrated  by  evaporation,  and 
then  the  requisite  proportion  of  potassium  in  the  form  of  the  sulphate 
or  chloride  is  added  to  the  hot  solution.  On  cooling,  the  alum  crys- 
tallizes out,  and  is  then  washed  and  recrystallized.  The  mother 
liquor  left  after  the  precipitation  is  revaporated  to  obtain  the  remain- 
ing alum  held  in  solution.  This  process  is  carried  on  extensively  in 
Germany,  France,  at  Whitby  in  Yorkshire,  Hurlett  and  Campsie, 
near  Glasgow,  in  Scotland.  Cape  Sable  in  Maryland  affords  large 
quantities  of  alum  annually.  The  slates  of  coal  beds  are  often  used 
to  advantage  in  this  manufacture,  owing  to  the  decomposing  pyrites 
present.  At  Whitby,  130  tons  of  calcined  schist  give  one  ton  of  alum. 
In  France,  ammoniacal  salts  are  used  instead  of  potash,  and  an  am- 
monia alum  is  formed. 

Alunite.— Alum  Stone. 

Khombohedral,  with  perfect  basal  cleavage.  Also  mas- 
sive. Color  white,  grayish,  or  reddish.  Lustre  of  crystals 
vitreous,  or  a  little  pearly  on  the  basal  plane.  Transparent 
to  translucent.  H.  =  4.  GL  =  2 '58-2 '75. 

Composition.  K2A1022S4 -f  6aq.  (or  K2OS03  -f  3A103 
S03  +  6aq.)  =  Sulphur  trioxide  38*5,  alumina  37*1, 
potash  11-4,  water  13*0  =  100.  B.B.  decrepitates,  infusi- 
ble; reaction  for  sulphur. 

Diff.  Distinguished  by  its  infusibility,  and  its  complete 
solubility  in  sulphuric  acid  without  forming  a  jelly. 


218  DESCRIPTIONS   OF   MINERALS. 

01  s.  Found  in  rocks  of  volcanic  origin  at  Tolfa,  near 
Rome;  and  also  at  Beregh  and  elsewhere  in  Hungary. 

When  calcined,  the  sulphates  become  soluble,  and  the 
alum  is  dissolved  out.  On  evaporation  the  alum  crystallizes 
from  the  fluid  in  cubic  crystals.  This  is  called  Roman 
alum,  and  is  highly  valued  by  dyers,  because,  although  the 
crystals  are  colored  red  by  iron  oxide,  no  iron  is  chemically 
combined  with  the  salt,  as  is  usual  in  common  alum. 

Aluminite  (Websterite).  Another  hydrous- aluminium  sulphate,  in 
compact  reniform  masses,  and  tasteless.  From  New  Haven,  in  Sussex; 
Epernay,  in  France;  and  Halle,  in  Prussia.  Werthemanite  is  a  related 
mineral  containing  less  water,  from  Chili ;  and  Picrallumogen  an- 
other, containing  about  8  p.  c.  of  magnesia. 

Jeremejefflte.  Aluminium  borate;  in  hexagonal  crystals.  W.  Si- 
beria. . 

PHOSPHATES. 
Amblygonite. — Lithium  -Aluminium  Phosphate. 

Triclinic,  with  cleavages  unequal  in  two  directions,  in- 
clined to  one  another  104^°.  Lustre  vitreous  to  pearly  and 
greasy.  Color  pale  mountain-green  or  sea-green  to  white. 
Translucent  to  subtransparent.  H.  =  6.  G.  =  3-3  •!!. 

Composition.  A  lithium-aluminium  phosphate,  A10eP2-j- 
(LiNa)2(FOH),  (or  A103  +  P205  +  [Li,NaJ  [FOH]).  B.B. 
fuses  very  easily  with  intumescence,  coloring  the  flame  yel- 
lowish red  to  rich  carmine-red,  owing  to  the  lithia  present, 
with  traces  of  green  owing  to  the  phosphoric  acid;  reaction 
also  for  fluorine. 

Obs.  Occurs  in  Saxony  and  Norway ;  at  Montebras 
(Montebrasite),  France  ;  Hebron  and  Mount  Mica  (Hebron- 
ite)  in  Maine;  Branchville,  Ct. 

Dwrangite.  Anhydrous  aluminium  arsenate,  containing  alumin- 
ium, sodium,  iron,  and  some  manganese,  with  over  7  per  cent,  of 
fluorine;  monoclinic;  orange-red;  Gk  =  8'9-*4-l.  Barranca  tin-mine, 
Durango,  Mexico,  with  cassiterite  or  tin  ore. 

Lazulite. 

Monoclinic.  In  crystals;  also  massive.  Color  azure-blue. 
H.=  5-6.  G.=  3-057. 

Composition.  RA109P2+aq= Phosphorus  pentoxide  46-8, 
alumina  34*0,  magnesia  13*2,  water  6*0=100.  B.B.  in  the 
closed  tube  whitens,  yields  water;  with  cobalt  solution  the 
color  is  restored;  in  the  forceps  whitens,  swells,  falls  to 
pieces  without  fusion,  coloring  the  flame  bluish  green. 


-ALUMINIUM.  219 

01) s.  From  Salzburg,  Styria;  Wermland,  Sweden;  Crowder 
Mount,  Lincoln  Co.,  N.  C. ;  Graves  Mountain,  Lincoln  Co., 
Ga. ;  Keewatin  Dist. ,  Canada. 

Varisdte  (Peganite,  Callamite).  A  hydrous  aluminium  phosphate; 
color  light  green,  of  various  shades,  to  deep  emerald -green.  From 
Montgomery  Co.,  Ark.;  Colorado;  Messbach,  in  Saxon  Voigtland. 
Fischer ite  is  a  related  mineral. 

Ecawite.  .  Hydrous  aluminium  phosphate;  looks  like  -allophane. 
Hungary. 

Goyazite.  Hydrous  aluminium-calcium  phosphate;  yellowish-white 
Minas  Geraes,  Brazil. 

Turquois. 

Massive,  reniform,  without  cleavage.  Color  bluish  green. 
Lustre  somewhat  waxy.  H.  —  6.  G.  =  2  '6-2  -8. 

Composition.  Phosphorus  pent  oxide  22'6,  alumina  46*9, 
water  20*5  =  100.  B.B.  infusible,  but  becomes  brown;  colors 
the  flame  green.  Soluble  in  hydrochloric  acid;  moistened 
with  the  acid,  gives  a  momentary  bluish  green  color  to  the 
flame,  owing  to  the  copper  present. 

Diff.  Distinguished  from  bluish  green  feldspar,-  which  it 
resembles,  by  its  infusibility  and  the  reactions  for  phos- 
phorus, 

Obs.  Found  in  a  mountainous  district-in  Persia,  not  far 
from  Mchabour;  N.  Mexico,  in  Los  Cerillos,  at  Mt.  Chal- 
chuitl,  22  m.  from  Santa  Fe;  in  Turquois  Mtn.,  Arizona;  in 
S.  Nevada,  5  m.  K  of  Columbus. 

The  Callais  of  Pliny  was  probably  turquois.  Pliny,  in  his 
description  of  it,  mentions  the  fable  that  it  was  found  in 
Asia,  projecting  from  the  surface  of  inaccessible  rocks, 
whence  it  was  obtained  by  means  of  slings. 

Receives  a  fine  polish  and  is  highly  esteemed  as  a  gem. 
The  Persian  king  is  said  to  retain  for  himself  all  the  large 
and  more  finely-tinted  specimens.  The  New  Mexico  locality 
affords  fine  gems.  Prof.  W.  P.  Blake  regards  the  turquois 
as  resulting  from  the  decomposition  of  a  trachyte.  The  occi- 
dental or  bone  turquois  is  fossil  teeth  or  bones,  colored  with 
a  littl  e  phosphate  of  iron.  Green  malachite  is  sometimes  sub- 
stituted for  turquois;  but  it  is  softer,  and  different  in  color. 
The  stone  is  so  well  imitated  by  art  as  scarcely  to  be  detected 
except  by  chemical  tests;  but  the  imitation  is  much  softer 
than  true  turquois. 

Ghildrenite.    Orthorhombic;  yellow  to  brown;  hydrous  phosphate, 


220  DESCRIPTIONS   OF  MINERALS. 

containing  aluminium,  iron,  with  little  manganese.  In  crystals  in 
Devonshire  and  Cornwall;  Hebron,  Me. 

Eosphorite  Has  the  crystalline  form  of  childrenite,  and  contains 
the  same  constituents,  but  differs  in  being  essentially  a  hydrous  phos- 
phate of  manganese  with  little  iron;  rose-red;  G.=3-l-3'5.  Branch- 
ville,  Connecticut. 

Henwoodite.  A  hydrous  aluminium-copper  phosphate,  of  turquois 
blue  color.  Cornwall,  on  limonite. 

Wavellite. 

Orthorhombic.  Usually  in  small  hemispheres  a  third  or 
half  an  inch  across,  finely  radiated 
within ;  when  broken  off  they 
leave  a  stellate  circle  on  the  rock. 
Sometimes  in  rhombic  crystals ; 
also  stalactitic. 

Color  white,  green,  or  yellowish 
and  brownish,  with  a  somewhat  pearly  or  resinous  lustre. 
Sometimes  gray  or  black.  Translucent.  H.  =  3  *5-4. 
G.  =  2-3-2  -34. 

Composition.  A13019P4-|-12  aq  (or  3A103-{-2P205+12  aq) 
=  Phosphorus  pentoxide  35-16,  alumina  38-10,  water  26 -74 
=  100.  1  to  2  per  cent,  of  fluorine  often  present,  replac- 
ing oxygen.  B.B.  whitens,  swells,  but  does  not  fuse. 
Colors  the  flame  green,  especially  if  moistened  with  sul- 
phuric acid;  moistened  with  cobalt  nitrate,  becomes  blue 
after  ignition;  gives  much  water  in  the  closed  glass  tube. 

Dlff.  Distinguished  from  the  zeolites,  some  of  which  it 
resembles,  by  giving  the  reaction  of  phosphorus,  and  also 
by  dissolving  in  acids  without  gelatinizing.  Cacoxene,  to 
which  it  is  allied,  becomes  dark  reddish  brown  B.B.,  and 
does  not  give  the  blue  with  cobalt  nitrate. 

Obs.  Slate  quarries  of  York  Co.,  Pa.;  Washington  Mine, 
Davidson  Co.,  N.  C.;  Magnet  Cove,  Ark.  First  discovered 
by  Dr.  Wavel  in  clay  slate  in  Devonshire.  Also  in  Bohe- 
mia and  Bavaria. 

Zepharomehite  is  near  wavellite. 

Liskeardite.  A.  hydrous  aluminium  arsenate;  incrusting;  white, 
bluish.  Cornwall. 

Mettite  or  Honey  stone.  In  square  octahedrons;  honey-yellow;  an 
aluminium  mellate.  Thuringia,  Bohemia,  Moravia,  etc. 

Aluminium  Carbonate. — Dawsonite.  Hydrous  aluminium -sodium 
carbonate,  an  analysis  afforded  Carbon  dioxide  27*78,  alumina  36*12, 
soda  22*86,  water  13 '24  =  100.  From  a  felsyte  dike  near  Montreal; 
Siena,  Tuscany. 


CERIUM,  YTTRIUM,  ERBIUM,  LANTHANUM,  DIDYMIUM.     221 

CERIUM,  YTTRIUM,  ERBIUM,  LANTHANUM,  DIDYMIUM. 

Known  in  nature  in  the  condition  of  fluorides,  tanta- 
lates,  columbates,  phosphates,  or  carbonates,  and  aLo  as 
constituents  in  several  silicates. 

Yttrogerite. 

Massive.  Color  violet-blue  (somewhat  resembling  purple 
fluorite) ;  also  reddish  brown.  Lustre  glistening.  Opaque. 
H.  =4-5.  G.  =  3-4-3-5. 

Composition.  Fluorine  25-1,  lime  47 '6,  cerium  protoxide 
18  -2,  y ttria  9  •  1 .  B.  B.  alone  infusible. 

Obs.  From  Finbo  and  Broddbo,  Sweden;  Mt.  Mica,  Me. ; 
probably  Worcester  Co.,  Mass.;  Amity,  Orange  Co.,  N.  Y. 

Tysonite.  Fluoride  of  cerium,  lanthanum,  and  didymium,  in  wax- 
yellow,  hexagonal  crystals.  Pike's  Peak,  Col. 

Fluocerite,  Fluocerine.  Other  fluorides  containing  cerium. 
Sweden. 

Samarskite. 

Orthorhombic;  I /\  I  =  122°  46'.  Usually  massive,  with- 
out cleavage.  Color  velvet-black.  Lustre  shining  submetal- 
lic.  Streak  dark  reddish  brown.  Opaque.  H.  =  5  -5-6. 
G.  =  5-6-5-8. 

Composition.  Analyses  of  the  American  afford  niobic  and" 
tantalic  pentoxide,  with  sesquioxides  of  yttrium  (12-15  per 
cent.),  cerium,  didymium,  and  lanthanum,  iron,  and  oxide 
of  uranium.  The  new  metals  terbium,  decipium,  phillipium 
have  been  reported  from  the  samarskite.  In  the  closed 
tube  decrepitates  and  glows.  B.B.  fuses  on  the  edges  to  a 
black  glass.  With  salt  of  phosphorus  in  both  flames,  an 
emerald-green  bead. 

Obs.  At  Miask,  in  the  Ural;  in  masses,  sometimes  weigh- 
ing many  pounds,  at  the  Mica  mines  of  Western  N.  Caro- 
lina, along  with  columbite;  rare  at  Middletown,  Ct. 

Nohlite  and  Vietinglwfite  are  near  samarskite. 

Fergmonite.  Hydrous  niobatc  of  yttrium,  erbium,  cerium;  brown- 
ish black;  lustre  brilliantly  vitreous  on  a  surface  of  fracture;  B.B.  in- 
fusible, but  loses  its  color.  Sweden ;  Cape  Farewell,  Greenland ; 
Rockport,  Mass.;  Burke  and  Mitchell  cos.,  N.  C. 

Kochelite.    Near  fcrgusonite.     Silesia. 

Anncrodite.  Orthorhombic;  black,  metallic  or  submetallic;  niobate 
of  uranium,  yttrium,  thorium,  cerium,  etc.  Annerod,  Norway. 

Yttro-lantalite.  A  tantalate  and  niobate  of  yttrium,  erbium  and 
iron;  different  varieties  are  the  black,  the  yellow,  and  the  brown  or 


DESCRIPTIONS   OF   MINERALS. 


dark-colored;  infusible.  Ytterby,  Sweden;  Broddbo  and  Finbo, 
near  Fahlun. 

Euxenite.  A  niobate  and  tantalate  of  yttrium,  uranium,  erbium, 
and  cerium;  massive;  brownish  black;  streak  reddish  brown;  B.B.  in- 
fusible. Norway. 

Sipylite.  A  niobate  and  tantalate  of  erbium  and  yttrium,  resembling 
fergusonite  in  aspect;  stated  to  contain  also  phillipiuin  and  ytterbium. 
Amherst  Co.,  Va. 

JEschynite.  Black  to  brownish  yellow;  resinous  to  submetallic; 
H.  =  5-6;  G.  =  4'9-5-l;  a  niobate  and  titanate  of  cerium,  thorium,  lan- 
thanum, didymium,  and  erbium.  Miask,  Urals;  Norway. 

Polymignite  and  Polycrase.     Related  to  a3schyuite.     Norway. 

Pyrochlore,  Microlite,  Disanalytc,  under  CALCIUM,  p.  234. 

Rogersite.  A  hydrous  yttrium  niobate;  in  whitish  crusts,  on  samar- 
skite.  From  Mitchell  Co.,  N.  C. 

Monazite. 

Mpnoclinic;  /A  7=93°  10',  C  =  76°  14'.     Perfect  and 
brilliant  basal  cleavage.  Observed  only  in  imbedded  crystals. 
Color  brown,  brownish  red;  subtrans- 
parent  to  nearly  opaque.     Lustre  vit- 
reous  inclining  to   resinous.     Brittle. 
H.  =  5.     G.  =4-8-5-1. 

Composition.  A  phosphate  of  cerium, 
lanthanum,  yttrium,  and  didymium. 
B.B.  colors  the  flame  green  when  moist- 
ened with  sulphuric  acid  and  heated, 
Difficultly  soluble  in  acids. 

Diff.  The  brilliant  easy  transverse 
cleavage  distinguishes  monazite  from 
sphene. 

Obs.  Occurs  near  Slatoust,  Russia;  at  Tavetsch  and  Bin- 
nenthal,  Switzerland  (Turner ite);  in  the  TJ.  States  in  small 
brown  crystals,  disseminated  through  a  mica  schist  at  Nor- 
wich and  Chester,  Ct. ;  also  at  Portland,  Ct. ;  Yorktown, 
"Westchester  Co.,  N.  Y.;  Alexander  Co.,  and  elsewhere, 
N.  C.;  Amelia  Co.,  Va.,  in  masses  of  8  pounds  and  less. 

Cryptolite.  A  cerium  phosphate;  in  minute  yellow  six-sided  prisms 
in  apatite.  Arendal,  Norway. 

Churchite.  Phosphate  of  cerium,  didymium,  and  calcium.  Corn- 
wall. 

Xenotime.  Yttrium  phosphate;  tetragonal,  lateral  cleavage  perfect; 
yellowish  brown;  opaque;  lustre  resinous;  H.  =4-5;  G.  =4'6;  B.B. 
infusible.  Lindesnaes,  Norway;  Ytterby,  Sweden;  gold-washings  of 
Clarkesville,  Ga.;  McDowell  and  Alexander  Cos.,  N.  C.;  near  Pike's 
Peak,  Col. 


MAGNESIUM.  223 

Bastndmte,  A  carbonate  of  cerium,  lanthanum,  and  dictymium, 
containing  fluorine.  Bastnas,  Sweden;  Pike's  Peak,  Col. 

RhdbdopJiane  (Scomllite).  Hydrous  phosphate  of  cerium,  lanthanum, 
and  didymium;  in  pink  and  brownish  incrustations  on  manganese  ore. 
Salisbury,  Ct.  Phosphocerite  is  the  same. 

Rutherfordite.  Blackish  brown;  vitreo-resinous.  Kutherford  Co., 
N.C. 

CAKBONATES. — Parisite.  A  carbonate  containing  cerium,  lan- 
thanum, and  didymium,  with  fluorine.  New  Granada. 

Lanthanite.  Hydrous  lanthanum  carbonate;  in  thin  minute  tables 
or  scales;  whitish  or  yellowish.  Bastnas,  Sweden;  Saucon  Valley, 
Lehigh  Co.,  Pa, 

Tengerite.     Yttrium  carbonate;  in  thin  coatings.     Ytterby. 

Allanite,  Gadolinite,  Keilhauite,  Tscheffkinite,  and  Erdmannite  are 
silicates  containing  either  cerium  or  yttrium. 

MAGNESIUM. 

Magnesium  occurs,  in  nature,  as  an  oxide  and  a  hydrated 
oxide,  and  in  the  condition  of  sulphate,  borate,  nitrate, 
phosphate,  carbonate,  and  silicate. 

The  sulphates  and  nitrate  of  magnesia  are  soluble  in 
water,  and  are  distinguished  by  their  bitter  taste;  the  other 
native  magnesian  salts  are  insoluble.  The  presence  of  mag- 
nesia in  infusible  species,  when  no  metallic  oxides  are  pre- 
sent, is  indicated  by  a  blowpipe  experiment  explained  on 
page  98. 

Periclasite. — Pcriclase.    Magnesium  Oxide. 

Isometric.  In  small  imbedded  crystals,  with  cubic  cleav- 
age. Color  grayish  to  dark  green.  H.  nearly  6.  G.  = 
3-674. 

Composition.  MgO  (or  the  same  as  for  magnesia  alia  of 
the  shops),  with  a  little  iron  as  impurity.  B.B.  infusible. 
Soluble  in  acids  without  effervescence. 

From  Mount  Somma,  Vesuvius,  Italy. 

Sellaife.  Tetragonal;  colorless;  transparent;  fuses  in  a  candle;  mag- 
nesium fluoride  (MgFl).  Geibroula,  Piedmont. 

Brucite. — Magnesium  Hydrate. 

Rhombohedral.  In  hexagonal  prisms  and  plates;  thin 
foliated,  the  thin  laminae  easily  separated ;  also  fibrous,  re- 
sembling amianthus  (Nemalite).  Translucent.  Flexible  but 
not  elastic.  Lustre  pearly.  Color  white,  often  grayish  or 
greenish.  H.  =  2  '5.  G.  =  2  -35-2  -45. 

Composition.  MgOaH2  (or  MgO  +  H20)=  Magnesia  69-0, 


224:  DESCRIPTIONS   OF  MINERALS. 

water  31 -0  =  100.  B.B.  infusible,  but  becomes  opaque  and 
alkaline.  Soluble  in  hydrochloric  acid  without  efferves- 
cence. Mangaribrutite  is  a  manganesian  variety. 

Diff.  Eesembles  talc  and  gypsum,  but  is  soluble  in 
acids ;  differs  from  heulandite  and  stilbite  also  by  its  inf  usi- 
bility. 

Obs.  Occurs  in  serpentine  at  Hoboken,  N.  J.;  Staten 
Island,  and  Brewster's,  N.  Y. ;  at  Texas,  Pa. ;  Swinaness, 
in  Unst,  one  of  the  Shetland  Isles. 

Pyroaurite  (Iglestromite).  Magnesium-iron  hydrate,  silvery  white 
to  golden.  Longban,  Wermland;  Scotland. 

Hydromagnesite.  White  pearly  crystalline,  or  earthy,  hydrous  car- 
bonate of  magnesia.  Hoboken,  N.  J. ;  Texas,  Pa. ;  and  elsewhere. 

Spinel  contains  oxygen  and  magnesium  along  with  aluminium.  See 
page  213.  Magnesium  is  also  present  in  some  magnetite,  a  variety  of 
which  is  called  Magneferrite. 

Nocerlne.    A  magnesium  calcium  fluoride;  from  Nocera  tufa. 

Ghlormagnesite.  Magnesium  chloride  from  Vesuvius.  Bischofile, 
from  a  salt  mine  in  Prussia,  is  probably  the  same. 

Carnallile.     Hydrous  magnesium-potassium  chloride.      Stassfurth. 

Tachhydrite.    Hydrous  magnesium-calcium  chloride.     Stassfurth. 

Epsomite. — Epsom  Salt.     Magnesium  Sulphate. 

Orthorhombic;  /A  /=  90°  34'.  Cleavage  perfect,  parallel 
with  the  shorter  diagonal.  Usually  in  fibrous  crusts  or 
botryoidal  masses.  Color  white.  Lustre  vitreous  to  earthy. 
Very  soluble;  taste  saline  bitter. 

Composition.  Mg04S  -f  7aq  (or  MgO  +  SO,  =  7aq)  = 
Sulphur  trioxide  32  -5,  magnesia  16*3,  water  51*2  =  100. 
Liquefies  in  its  water  of  crystallization  when  heated.  Gives 
much  water,  acid  in  reaction,  in  the  closed  tube. 

Diff.  The  fine  spicula-like  crystalline  grains  of  Epsom 
salt,  as  it  appears  in  the  shops,  distinguish  it  from  Glauber 
salt,  which  occurs  usually  in  thick  crystals. 

Obs.  Occurs  as  an  efflorescence  in  the  galleries  of  mines 
and  elsewhere.  Sometimes  in  minute  crystals  mingled  with 
the  earth  of  the  floors  of  caves.  In  the  Mammoth  Cave, 
Ky.,  it  adheres  to  the  roof  in  loose  masses  like  snowballs. 
The  fine  efflorescences  suggested  the  old  name  hair-salt. 

Occurs  dissolved  in  mineral  springs  at  Epsom,  in  Surrey, 
England,  and  thence  the  name  it  bears;  at  Sedlitz,  Aragon; 
in  a  grotto  in  Southern  Africa,  a  layer  an  inch  and  a  half 
thick;  massive  (Reichardt ite)  at  Stassfurth. 

Its  medical  uses  are  well  Known.     It  is  obtained  for  the 


MAGNESIUM. 


225 


arts  from  the  bittern  of  sea-salt  works,  but  now  chiefly 
from  dolomite  or  magnesite,  by  decomposing  with  sulphuric 
acid. 

Polyhalite.  Hydrous  calcium-magnesium  sulphate;  massive,  some- 
what fibrous  in  appearance;  brick-red;  taste  weak.  Bitter.  Isclil  and 
other  salt-mines.  Krugiie  is  similar. 

Kieserite.     Hydrous  magnesium  sulphate.     Stassfurth. 

Picromerite.  Hydrous  potassium  -  magnesium  sulphate;  white. 
Stassfurth.  Kainite,  sulphato-chloridc  of  same  bases. 

Blcsdite.  A  hydrous  sodium-magnesium  sulphate.  Salt-mines  of 
Ischl ;  near  Mendoza.  Simonyite  is  related ;  from  Hallstadt. 

Lmweite.  A  hydrous  sodium-magnesium  sulphate  ;  contains  more 
sulphur  trioxide  than  Blcedite.  Ischl. 


Isometric. 


Boracite. — Magnesium  Borate. 

Usual  in  small  cubes;  with  the  alternate 

angles  replaced,  or  with  all 

replaced   but  four  of  them  2 

differently   from  the  other 

four.        Cleavage     only    in 

traces.      Also  massive.     In 

crystals,  translucent'.    Color 

white  or  grayish;  yellowish 

or  greenish.  Lustre  vitreous. 

H.    of  crystals  =  7  ;    when 

massive,  softer.    G.  =  2-97.    Becomes  electric  when  heated, 
with  the  opposite  angles  of  the  cube  of  opposite  polarity. 

Composition.  Mg3O1BB8  -f  JMgCl,  (or  3MgO  +  4B203  + 
•JMgClJ  =  Boron  trioxide  62'0,  magnesia  31*0,  chlorine 
7'0  =  100.  B.B.  fuses  easily  with  intumescence,  coloring 
the  flame  green;  globule  crystalline  on  cooling.  Dissolves 
in  hydrochloric  acid;  wet  with  cobalt  nitrate  turns  pink  on 
ignition. 

Diff.  Distinguished  readily  by  its  form,  high  hardness, 
and  pyro-electric  properties. 

Obs.  With  gypsum  and  common  salt,  near  Liineburg  in 
Saxony;  near  Kiel,  Prussia;  also  at  Stassfurth. 


Rhodizite.    Like  boracite  in  its  crystals,  but 
flame  deep  red;  supposed  to  be  a  lime-boracite. 
in  Siberia. 

Ludwigite.    A  magnesium-iron  berate;  fibrous; 

Szaibelyite.     A  hydrous  magnesium   borate. 
is  another;  Stassfurth. 

Warwickile.    In  rhombic  prisms  of  93°  to  94° ;  hair-brown  to  black 


tinges  the  blowpipe 
With  red  tourmaline 

dark  green  to  black. 
Hungary.     Pinnoite 


226  DESCRIPTIONS   OF   MINERALS. 

•with  sometimes  a  copper-red  tinge;  a  magnesium-titanium  borate. 
Edenville,  N.  Y.,  in  crystalline  limestone. 

Smsexite.  A.  hydrous  magnesium-manganese  borate;  fibrous  and 
pearly;  G.  =  3'42.  Mine  Hill,  Franklin  Furnace,  Sussex  Co.,  N.  J. 

Nitromagnesite.  Magnesium  nitrate;  in  white  deliquescent  efflores- 
cences, having  a  bitter  taste.  With  calcium  nitrate,  in  limestone 
caverns.  Used,  like  its  associate,  in  the  manufacture  of  saltpetre. 

Wagnerite.  A  magnesium  fluo- phosphate;  yellowish  or  grayish  ob- 
lique rhombic  prisms;  insoluble;  H.  =  5-5'5;  G.  =  3'1.  Salzburg, 
Austria.  Kjerulfine  is  wagnerite. 

Newberyite.  Orthorhombic  tabular  crystals,  from  guano;  hydrous 
magnesium  phosphate.  Skipton  Caves,  Victoria. 

Hcernisite  and  Rwsslerite.     White  hydrous  magnesium  arsenates. 

Luneburgite.    A  magnesium  boro-phosphate.    Limeburg. 

Magnesite. — Magnesium  Carbonate. 

Ehombohedral;  R  :  R  =  107°  29'.  Cleavage  rhombohe- 
dral,  perfect.  Often  massive,  either  granular,  or  compact 
and  porcelain-like,  in  tuberose  forms;  also  fibrous. 

Color  white,  yellowish  or  grayish  white,  brown.  Lustre 
vitreous;  fibrous  varieties  often  silky.  Transparent  to 
opaque.  H.  =  3-4*5  G.  —  3;  3-3 '2  when  ferriferous. 

Composition.  Mg03C  (or  MgO  -f-  COJ  =  Carbon  dioxide 
52 '4,  magnesia  47  '6  =  100.  B.  B.  infusible ;  after  ignition,  an 
alkaline  reaction;  nearly  insoluble  in  cold  dilute  hydrochloric 
acid,  but  dissolves  with  effervescence  in  hot. 

Diff.  Eesembles  some  calcite  and  dolomite;  but  from  a 
concentrated  solution  no  calcium  sulphate  is  precipitated 
on  adding  sulphuric  acid.  The  fibrous  variety  is  distin- 
guished from  most  other  fibrous  minerals  by  effervescence 
in  hot  acid,  which  shows  it  to  be  a  carbonate. 

Breunnerite  is  a  magnesite  containing  iron;  turns  brown 
on  exposure. 

Obs.  Usually  associated  with  magnesian  rocks,  especially 
serpentine.  At  Hoboken,  N.  J.,  in  fibrous  seams;  similarly 
at  Lynnfield,  Mass. ;  Texas,  Pa. ;  Bare  Hills,  Md. ;  in  Canada, 
at  Bolton,  massive  and  imperfectly  fibrous,  traversing  white 
limestone. 

A  convenient  material  for  the  manufacture  of  magnesium 
sulphate  or  Epsom  salt,  to  make  which  requires  simply 
treatment  with  sulphuric  acid,  and  so  used  on  a  large  scale 
in  Maryland  and  Pennsylvania. 

Hydromagnesite.  A  hydrous  magnesium  carbonate;  contains  about 
20  p.  c.  of  water.  With  serpentine.  Hoboken,  N.  J. ;  Texas,  Pa. 

Hydrogiobertite  is  similar,  but  gave  29 '93  p.  c.  of  water  and  less 
CO8.  From  Pollenza,  Italy. 


CALCIUM. 


227 


CALCIUM. 

Calcium  exists  in  nature  in  the  state  of  fluorite,  and  this 
is  its  only  native  binary  compound.  It  occurs  in  ternaries 
in  the  state  of  sulphate,  borate,  columbate,  phosphate,  ar- 
senate,  carbonate,  titanate,  oxalate,  and  silicate.  The  car- 
bonate (calcite  and  limestone)  is  one  of  the  three  most  abun- 
dant of  minerals.  The  fluoride  and  sulphate,  and  some 
silicates,  are  also  of  very  common  occurrence. 

With  the  exception  of  the  calcium  nitrate,  none  of  the 
native  salts  of  lime  are  soluble  in  water  except  in  small 
proportions.  Before  the  blowpipe  they  give  no  odor,  and 
no  metallic  reaction;  but  they  tinge  the  flame  red;  and 
many  of  them  give  up  a  part  of  their  acid  constituent,  and 
become  caustic  and  react  alkaline.  The  specific  gravity  is 
below  3  *2,  and  hardness  not  above  5. 

Fluorite. — Fluor  Spar.     Calcium  Fluoride. 

Isometric;  Figs.  1  to  4.  Cubes  most  common.  Cleavage 
octahedral,  perfect.  Rarely  fibrous;  often  compact,  coarse, 
or  fine  granular. 


2. 


Colors  usually  bright;  white,  or  some  shade  of  light 
green,  purple,  or  clear  yellow  most  common;  rarely  rose-red 
and  sky-blue;  colors  of  massive  varieties  often  banded. 
Transparent,  translucent,  or  subtranslucent.  H.  =  4. 
G.  =  3-3-25.  Brittle. 

Composition.  CaF,  —  Fluorine  48 '7,  calcium  51 -3  =  100. 
Phosphoresces  when  gently  heated  (as  seen  in  the  dark), 
affording  light  of  different  colors,  as  emerald-green,  purple, 
blue,  rose-red,  pink,  orange.  B.B.  decrepitates,  and  ulti- 
mately fuses  to  an  enamel,  having  an  alkaline  reaction; 
treated  in  powder  with  sulphuric  acid,  hydrofluoric  acid 
gas  is  given  off  which  corrodes  glass.  Ohlorophane  is  the 
kind  affording  a  bright  green  phosphorescence. 


228  DESCRIPTIONS  OF  MINERALS. 

Diff.  In  its  bright  colors,  fluorite  resembles  some  of  the 
gems,  but  its  softness  and  its  easy  octahedral  cleavage  when 
crystallized  at  once  distinguish  it.  Its  strong  phosphores- 
cence is  a  striking  characteristic ;  and  also  its  affording 
easily,  with  sulphuric  acid  and  heat,  a  gas  that  corrodes 
glass. 

Obs.  Fluorite  occurs  in  gneiss,  mica  schist,  clay  slate, 
limestone,  and  sparingly  in  beds  of  coal  either  in  veins  or 
occupying  cavities,  or  as  imbedded  masses.  It  is  the 
gangue  in  some  lead-mines. 

Cubic  crystals  of  a  greenish  color,  over  a  foot  each  way, 
have  been  obtained  at  Muscolonge  Lake,  St.  Lawrence 
County,  "S.  Y. ;  near  Shawneetown  on  the  Ohio,  a  beautiful 
purple  fluor  in  grouped  cubes  of  large  size  is  obtained  from 
limestone  and  the  soil  of  the  region;  at  Westmoreland,  N. 
H.,  at  the  Notch  in  the  White  Mountains;  Blue  Hill  Bay, 
Maine;  Putney,  Vt.;  Lockport,  N.  Y.;  Boulder  Co.,  Cal.; 
Crystal  Park,  El  Paso  Co.,  Col.;  Montana;  Wyoming;  N. 
Mexico;  Pike's  Peak,  Col.  Chlorophane  var.  at  Trumbull, 
Ct.,  and  Amelia  Court  House,  Va. 

In  Derbyshire,  England,  abundant,  and  hence  the  name 
Derbyshire  spar.  A  common  mineral  in  the  mining  dis- 
tricts of  Saxony. 

Calcium  fluoride  exists  in  the  enamel  of  teeth,  in  bones, 
and  some  other  parts  of  animals;  also  in  certain  parts  of 
many  plants;  and  by  vegetable  or  animal  decomposition  it  is 
afforded  to  the  soil,  to  rocks>  and  also  to  coal-beds  in  which 
it  has  been  detected. 

Massive  fluorite  receives  a  high  polish,  and  is  worked  into 
vases  and  various  ornaments  in  Derbyshire,  England. 
Some  of  the  varieties  from  this  locality,  consisting  of  rich 
purple  bands  alternating  with  yellowish  white,  are  very 
beautiful.  The  mineral  is  difficult  to  work  because  brittle. 
Fluorite  is  also  used  to  obtain  hydrofluoric  acid  for  etch- 
ing. To  etch  glass,  a  picture,  or  whatever  design  it  is  de- 
sired to  etch,  is  traced  in  the  thin  coating  of  wax  with 
which  the  glass  is  first  covered;  a  very  small  quantity  of  the 
liquid  hydrofluoric  acid  is  then  washed  over  it;  on  remov- 
ing the  wax,  in  a  few  minutes,  the  picture  is  found  to  be 
engraved  on  the  glass.  The  same  process  is  used  for  etch- 
ing seals,  and  any  siliceous  stone  will  be  attacked  with 
equal  facility.  This  application  of  fluor  spar  depends  upon 
the  strong  affinity  between  fluorine  and  silicon.  Fluor, 


s 


CALCIUM.  229 

spar  is  also  used  as  a  flux  to  aid  in  reducing  copper  and 
other  ores,  and  hence  the  n&meflicor. 
Chlorocalcite  (Eydrophilite).    Calcium  chloride.    Vesuvius,  Peru. 

Gypsum. — Hydrous  Calcium  Sulphate. 

Monoclinic;  I/\I=  143°  42';  21 A  21  =  111°  42'.  Fig. 
2,  a  common  twin  (or  arrow-head) 
crystal.  Cleavage  parallel  to  broad 
face  in  Fig.  1,  very  easy,  affording 
thin  pearly  flexible  laminae;  in  a  cross 
direction,  imperfect.  Also  in  lami- 
nated masses;  fibrous,  with  a  satin 
lustre;  in  stellated  or  radiating  forms 
consisting  of  narrow  laminae ;  also 
granular  and  compact. 

When  crystallized  usually  trans- 
parent or  nearly  so ;  the  massive,  translucent  to  opaque. 
Lustre  pearly.  Color  white,  gray,  yellow,  reddish,  brown- 
ish, and  even  black.  H.  —  1-5-2,  or  so  soft  as  to  be 
scratched  by  the  finger-nail.  G.  =  2  -33.  The  plates  bend 
in  one  direction  and  are  brittle  in  another. 

Composition.  Ca04S  -|-  2  aq  (or  CaO  +  S03  +  2  aq)  = 
Sulphur  trioxide  46-5,  lime  32  6,  water  20-9  =  100.  B.B. 
becomes  instantly  white  and  opaque  and  exfoliates;  then 
fuses  to  a  globule,  having  an  alkaline  reaction.  In  a  closed 
tube  much  water  is  given  off.  Dissolves  quietly  in  hydro- 
chloric acid,  and  the  solution  gives  a  heavy  precipitate  with 
barium  chloride. 

The  principal  varieties  are  as  follows: 
Selenite :  in  transparent  plates  or  crystal.     Named  from 
selene,  the  Greek  for  moon,  alluding  to  the  pearl-white  ap- 
pearance. 

Radiated  and  Plumose  gypsum :  radiated  in  structure. 
Fibrous  gypsum,  Satin  spar:  white  and  delicately  fibrous. 
Snowy  gypsum  and  Alabaster:  include  the  white  or  light- 
colored  compact  gypsum  having  a  very  fine  grain. 

Diff.  Foliated  gypsum  resembles  some  varieties  of  heu- 
landite,  stilbite,  talc,  and  mica;  and  the  fibrous  looks  like 
fibrous  carbonate  of  lime,  asbestus  and  some  of  the  fibrous 
zeolites;  but  gypsum  in  all  its  varieties  is  readily  distin- 
guished by  its  softness;  its  becoming  B.B.  opaque  white 
through  loss  of  water  without  fusion  ;  by  not  effervescing 
or  gelatinizing  with  acids.  Moreover,  on  adding  a  little 


230  DESCRIPTIONS   OF  MINERALS. 

water  to  the  powder  obtained  by  heating,  the  water  is  taken 
up  and  the  whole  becomes  solid. 

Obs.  Gypsum  forms  extensive  beds  in  certain  limestones 
and  clay  beds,  and  also  occurs  in  volcanic  regions.  Selenite 
and  snowy  gypsum  occurs  in  limestone  near  Lockport,  at 
Camillus,  Manlius,  and  Troy,  N.  Y.;  in  Davidson  Co., 
Tenn.  ;  crystals  (Fig.  1),  at  Poland  and  Canfield,  Ohio ; 
groups  of  crystals  at  St.  Mary's  in  Maryland ;  in  Mammoth 
Cave,  Ky.,  alabaster,  in  imitation  of  flowers,  leaves,  shrub- 
bery, and  vines.  Alabaster  is  obtained  at  Castelino  in  Italy, 
35  miles  from  Leghorn.  Massive  gypsum  is  abundant  in 
N.  York,  from  Syracuse  to  the  western  extremity  of  Gene- 
see  County;  in  New  Brunswick,  especially  at  Hillsboro', 
where  part  is  excellent  alabaster ;  in  Hants,  Colchester,  and 
other  districts,  Nova  Scotia;  in  Ohio,  Michigan,  Illinois, 
Virginia,  Tennessee,  Kansas,  Arkansas,  Texas,  Iowa ;  and  in 
connection  with  the  Triassic  beds  of  the  Rocky  Mountain 
region,  abundant  in  Nevada,  California,  Colorado,  Montana, 
Dakota,  N.  Mexico,  Arizona.  Abundant  also  in  Europe. 

Gypsum,  when  calcined  and  reduced  to  powder,  is  plas- 
ter of  pans,  and  is  used  for  taking  casts,  making  models, 
and  for  giving  a  hard  finish  to  walls.  Alabaster  is  cut  into 
vases  and  various  ornaments,  statues,  etc.  It  owes  its 
beauty  for  this  purpose  to  its  snowy  whiteness,  translucency, 
and  fine  texture.  Moreover,  owing  to  its  softness,  it  can 
be  cut  or  carved  with  common  cutting  instruments.  Ground 
gypsum  is  used  for  improving  soils. 

Anhydrite. — Anhydrous  Calcium  Sulphate. 

Orthorhombic;  7  A  7=100°  30';  HAH  =  85°  and  95°. 
In  rectangular  and  rhombic  prisms ;  cleaves  easily  in  three 
directions,  into   square   blocks.      Also  fi- 
brous and  lamellar,  often  contorted;  coarse 
and  fine  granular,  and  compact. 

Color  white,  or  tinged  with  gray,  red, 
or  blue.  Lustre  more  or  less  pearly. 
Transparent  to  subtranslucent.  H.  = 
3-3-5.  G.  =  2-95-2-97. 

Composition.  Ca04S  (or  CaO  -f  S03)  = 
Sulphur  trioxide   58  '8,  lime  41-2-100. 
It  is  an  anhydrous  calcium  sulphate.    B.  B. 
and  with  acids,  its  reactions  are  like  those 
of  gypsum,  except  that  in  the  closed  tube  it  gives  no  water. 


CALCIUM.  231 

A  scaly  massive  variety  containing  a  little  silica  has  been 
named  Vulpinite;  contorted  concretionary  kinds  are  some- 
times called  Tripestone.  Anhydrite  is  called  by  miners 
hard-plaster,  because  harder  than  gypsum. 

Diff.  Its  square  forms  of  crystallization  and  its  breaking 
or  cleaving  into  square  blocks  are  good  distinguishing  char- 
acters ;  it  looks  as  if  the  crystallization  were "  cubic ;  but 
there  is  some  difference  in  the  ease  of  cleavage  in  the 
three  directions. 

Obs.  Fine  blue  with  gypsum  and  calc  spar  in  black  lime- 
stone at  Lockport,  N.  Y.;  near  Windsor,  N.  Scotia;  at 
Hillsboro',  N".  Brunswick.  Foreign  localities  are  at  the 
salt-mines  of  Bex  in  Switzerland,  Hall  in  the  Tyrol,  Ischl 
in  Upper  Austria,  Wieliczka  in  Poland,  and  elsewhere. 

The  vulpinite  variety  is  sometimes  cut  and  polished  for 
ornamental  purposes. 

EttringHe.  Hydrous  calcium-aluminium  sulphate;  in  minute  hexag- 
onal crystals.  District  of  Laach,  in  limestone. 

Ulexite.— Boronatrocalcite.     Calcium-sodium  Borate. 

In  interwoven  fibres,  or  capillary  crystals,  making  small 
rounded  masses.  H.  =  1.  G.  =  1*65.  Lustre  silky.  Color 
white  to  gray.  Tasteless. 

Composition.  Hydrous  calcium-sodium  borate.  B.B. 
fuses  very  easily;  wet  with  sulphuric  acid  and  heated  B.B. 
the  flame  is  momentarily  deep  green. 

Obs.  From  the  dry  plains  of  Iquique,  and  in  Tarapaca, 
between  Peru  and  Chili ;  Windsor,  Brookville,  and  New- 
port, N.  Scotia ;  Columbus  Marsh  and  Thiel  Salt  Marsh, 
Nev.,  alternating  with  layers  of  salt. 

Valuable  as  a  source  of  borax.  Frariklandite  is  similar  ; 
from  Peru. 

Bechilite.  A  hydrous  calcium  borate.  Occurs  as  an  incrustation  at 
the  Tuscan  lagoons,  Italy.  A  "hydrous  borate  of  lime"  reported  by 
Hayes  from  Iquique,  Peru,  has  been  called  Hayesine;  but  its  compo- 
sition has  been  questioned,  it  being  referred  to  Ulexite. 

Priceite.  A  hydrous  calcium  borate;  white,  chalky;  G.  =  2'262; 
formula  deduced  Ca3Oj  5B4  +  6  aq  (or  3CaO  -f-  4BO3  -f  6  aq).  Forms  a 
compact  layer  and  large  masses,  5  m.  N.  of  Chetko,  in  Curry  Co., 
Oregon.  Cryptomorphite  may  be  the  same  as  priceite;  and  if  so  has 
priority  in  name.  Windsor,  JN".  Scotia. 

Pandermite.  Like  priceite;  H.  —  3;  G.  =  2'48;  formula  deduced 
Ca3OnB-3  +  3  aq.  In  gray  gypsum.  Panderma,  Black  Sea. 

Colenianite.    Like  pandermite  in  formula  except  5  aq  for  3  aq. 


232  DESCRIPTIONS   OF   MINERALS. 

monoclinic;  in  fine  glassy  crystals,  white  to  colorless,  and  massive; 
H.  =4.  G.  =  2'43.  San  Bernardino  Co.  and  Death  Valley  in  Invo 
Co.,  Cal. 

Hydroboracite.  A  hydrous  calcium-magnesium  borate,  resembling 
gypsum  in  aspect. 

Howlite.  A  hydrous  calcium  borate  containing  silica  ;  Windsor, 
Nova  Scotia  ;  called  also  Silicoborocalcite. 

Scheelite. — Calcium  Tungstate. 

Tetragonal.  Also  massive.  Lustre  vitreous,  inclining 
to  adamantine.  Color  white,  pale  yellowish,  brownish, 
greenish,  reddish.  Transparent-translucent.  H.  =  4-5-5. 
G.  =5-9-6-1. 

Composition.  Ca04W  (or  CaO  -f  W03).  B.B.  fuses  with 
much  difficulty  to  a  transparent  glass.  Cuproscheelite  has 
part  of  the  calcium  replaced  by  copper. 

Diff.  Unlike  calcite,  and  other  minerals  like  it,  in  its  high 
specific  gravity,  and  non-effervescence  with  acids. 

Obs.  From  Monroe,  Ct. ;  Flowe  Mine,  N.  C. ;  with  gold, 
at  Warren  Mine,  Idaho,  and  Golden  Queen  Mine,  in 
Colorado;  in  Mammoth  Mining  Dist.,  Nev.;  Seattle,  Wash- 
ington T. ;  Caldbeck  Fell,  England ;  in  Bohemia  ;  Hartz ; 
Saxony;  Hungary;  Sweden ;  Vosges ;  Adelong,  N.  S.  W. 

Apatite. — Calcium  Phosphate. 

Hexagonal.  Usually  in  hexagonal  prisms ;  0  A  1  = 
139°  42'.  Cleavage  imperfect.  Occasionally  massive ; 
sometimes  mammillary  with  a  compact  fibrous  structure. 
Color  usually  greenish,  often  yellowish  green, 
bluish  green,  and  grayish  green ;  sometimes 
yellow,  blue,  reddish,  brownish,  colorless. 
Lustre  vitreous  to  subresinous.  Transpar- 
ent to  opaque.  H.  =5.  G.  =  318-3-25. 
Brittle. 

Composition.  Ca308P,  -f  iCa(C!2,  F2)  (or 
3CaO  +  P205  +  iOa(01a,  F2)  =  if  without 
fluorine,  Phosphorus  pentoxide  40*92,  lime 
53*80,  chlorine  6*82  =  100.  When  chlorine  is  present  in 
place  of  fluorine  it  is  called  clilor-apatite,  and  when  the  re- 
verse, fluor-apatite.  B.B.  infusible  except  on  the  edges. 
Dissolves  slowly  in  nitric  acid  without  effervescence.  Some 
varieties  phosphoresce  when  heated,  and  some  become  elec- 
tric by  friction.  Its  constituents  are  contained  in  the  bones 


CALCIUM.  233 

and  ligaments  of  animals,  and  the  mineral  has  probably  been 
derived  in  many  cases  from  animal  remains.* 

Massive  apatite  is  often  called  Phosphorite;  the  pale  yel- 
lowish-green crystals,  Asparagus  stone.  Osteolite  is  a  white 
earthy  apatite.  Eupyrchroite  is  a  fibrous  mammillary  variety 
from  Crown  Point,  Essex  Co.,  N.  Y. 

Fossil  excrements,  called  coprolites,  occur  in  stratified 
rocks,  and  the  material  sometimes  constitutes  extensive 
beds;  it  is  chiefly  calcium  phosphate.  Guano  is  of  this 
origin,  and  consists  of  calcium  phosphate  along  with  more 
or  less  of  hydrous  phosphates  and  some  impurities. 

Diff.  Distinguished  from  beryl  by  its  inferior  hardness, 
it  being  easily  scratched  with  a  knife ;  from  calcite  by  no 
effervescence  with  acids;  from  pyromorphite  by  its  difficult 
fusibility,  and  giving  B.B.  no  metallic  reaction. 

Obs.  Apatite  occurs  in  gneiss,  mica  schist,  hornblende 
schist,  granular  limestone.  In  microscopic  crystals  it  is 
sparingly  present  in  almost  all  crystalline  rocks,  the  ig- 
neous as  well  as  metamorphic.  The  best  crystals  in  the 
United  States  occur  in  granular  limestone. 

Large  deposits  occur  in  veins  in  the  Archaean  of  Canada, 
especially  the  Ottawa  region,  which  contain  also  much 
calcite  and  pyroxene,  hornblende,  phlogopite  mica,  and 
often  zircon,  titanite,  scapolite,  and  other  minerals.  Some 
of  the  crystals  of  apatite  in  the  veins  are  one  to  two 
feet  in  diameter,  and  weigh  hundreds  of  pounds.  The 
veins  are  extensively  worked,  producing  20,000  to  25,000 
tons  a  year. 

Other  localities  are  Edenville  and  Amity,  Orange  Co., 
N".  Y. ;  Westmoreland,  N.  H.,  in  a  vein  of  feldspar  and 
quartz;  Blue  Hill  Bay,  Auburn,  Me.;  Bolton,  Chester- 
field, Chester,  Mass.;  beautiful  blue  at  Dixon's  quarry, 
Wilmington,  Del. 

Named  from  the  Greek  apatao,  to  deceive,  in  allusion  to 
the  mistake  of  early  mineralogists  respecting  the  nature  of 
some  of  its  varieties. 

When  abundant,  used,  like  guano,  as  a  fertilizer,  on  ac- 
count of  its  phosphoric  acid.  To  make  it  capable  of  being 
taken  up  by  plants  it  is  treated  first  with  a  small  portion  of 
sulphuric  acid,  which  renders  the  phosphoric  acid  soluble. 

*  Bones  contain  25  per  cent,  of  calcium  phosphate,  with  some  fluoride  of  cal- 
cium, 3  to  12  per  cent,  of  calcium  carbonate,  some  magnesium  phosphate  and 
sodium  chloride,  besides  33  per  cent,  of  animal  matter. 


234  DESCRIPTIONS   OF   MINERALS. 

When  guano  has  been  accumulated  by  birds,  or  other  ani- 
mals, over-  coral  rock,  a  calcium  carbonate,  (as  on  some 
coral  islands,)  the  waters  in  filtrating  through  it  have  often 
carried  down  the  soluble  phosphoric  acid  or  phosphates 
into  the  underlying  beds,  turning  them  into  calcium  phos- 
phate. 

Spodioaite  is  probably  an  apatite  pseudomorph. 

Herderite.  Calcium -beryllium  fluo-phosphate;  orthorhombic;  yel- 
lowish, greenish  white.  Ehrenfriedersdorf,  Saxony;  Stoneham,  Me. 

Brushite  and  Metabrushite.  Hydrous  calcium  phosphates.  Found 
in  guano.  Monetite  and  monite  are  other  guano  substances. 

PyrophospJwrite.  A  white,  earthy  phosphate;  analysis  gave  it  the 
composition  of  a  pyrophosphate.  A  guano  deposit  in  the  W.  Indies, 

Pharmacolite.     A  hydrous  calcium  arsenate. 

Haidingerite.     Another  hydrous  calcium  arsenate. 

Berzeliite.  Calcium-magnesium  arsenate;  isometric;  yellow;  G.  = 
4-4'l.  Caryinite  is  related  in  composition  but  is  not  isometric.  Both 
from  Longban,  Sweden. 

Nitrocalcite.    Hydrous  calcium  nitrate.    From  caverns. 

Pyrochlore.  A  calcium-cerium  niobate;  in  small  brown  and  brown- 
ish yellow  isometric  octahedrons;  G.  =  4*3-4 '5.  Norway;  Miask, 
Siberia. 

Microlite.  In  isometric  octahedrons,  like  pyrochlore;  color  brown; 
G.  =  55-6,  in  composition  a  calcium  tantalate.  Chesterfield,  Mass., 
Branch ville,  Ct.;  Amelia  Co.,  Va.,  Uto,  Sweden.  The  crystals  first 
found  were  small,  whence  the  name;  but  some  Virginia  crystals  weigh 
four  pounds, 

Disanalyte.  Acolumbate  and  titanate  of  calcium,  cerium,  and  iron; 
in  cubes.  The  Kaiserstuhl,  in  granular  limestone. 

Romeite,     Calcium  antimonate;  tetragonal;  yellow. 

Atopite  Another  calcium  antimonate  in  isometric  crystals.  Swe- 
den. Schneebergite  is  another. 

Calcite. — Calc  Spar.     Calcium  Carbonate. 

Rhombohedral;  R  A  R  (Fig.  1)  =  105°  5'.  Cleavage 
easy,  parallel  with  R.  Often  fibrous ;  lustre  silky  ;  some- 
times lamellar ;  often  coarse  or  fine  granular,  and  com- 
pact. 

Color ;  when  transparent,  colorless,  topaz-yellow,  and 
rarely  rose  or  violet;  other  crystalline  varieties,  white,  gray, 
reddish,  yellowish,  rarely  deep  red,  often  mottled;  when 
massive  uncrystalline,  of  various  dull  shades,  chalk-white, 
grayish  white,  gray,  ochre-yellow,  red,  brown,  and  black. 
Lustre  vitreous ;  of  the  finely  fibrous,  silky ;  of  the  uncrys- 
talline, dull,  often  earthy.  H.  =  3.  G-.  of  pure  crystals 
2-715;  2-5-2-8. 


CALCIUM. 


235 


Composition.  CaOaC  (or  CaO  +  C0a)  =  Carbon  dioxide 
44,  lime  56  =  100.  Sometimes  impure  from  mixture  with 
other  substances.  B.  B.  infusible ;  colors  the  flame  reddish ; 
gives  up  its  carbon  dioxide,  and  becomes  caustic,  and  alka- 
line in  reaction ;  and  by  this  process,  carried  on  in  lime- 


1. 


6. 


kilns,  limestone  is  burnt  to  quicklime.  Effervesces  in  dilute 
cold  hydrochloric  acid.  Many  varieties  phosphoresce  when 
heated. 

The  following  are  the  principal  varieties : 

Iceland  spar.  Transparent  crystalline  calcite ;  formerly 
brought  in  large  crystals  from  Iceland. 

Dog-tooth  spar.     Has  the  form  in  Fig.  7. 

Satin  spar.  Finely  fibrous,  with  a  satin  lustre.  Usually 
in  veins. 

Limestone.  A  general  name  for  massive  calcite  as  well 
as  for  massive  dolomite. 

Granular  limestone.  Lustre  glistening,  owing  to  its  con- 
sisting of  crystalline  grains;  the  grains  show  the  cleavages 
of  crystals  of  calcite.  Hence  called  crystalline  limestone. 
The  better  kinds,  valuable  in  the  arts,  are  called  marble; 
the  coarser  of  them,  architectural  marble ;  the  finer  white, 
statuary  marble;  colored  kinds,  as  well  as  white,  when 
polished,  ornamental  marbles.  The  best  marble  is  as  white 
and  fine-grained  as  loaf-sugar,  which  it  much  resembles. 
Often  impure  with  pyrite,  mica,  tremolite,  and  other  min- 
erals. 

Compact  limestone.     Dull  in  lustre  unless  polished,  and 


236  DESCRIPTIONS   OF   MINERALS. 

not  distinctly  granular  in  texture.  Colors  sometimes  ar- 
ranged in  blotches  or  veins.  The  kinds  that  are  handsome 
when  polished  and  fit  for  ornamental  purposes  are  include'd 
among  marbles. 

Chalk.  White  and  earthy ;  without  lustre ;  so  soft  as 
to  leave  a  trace  on  a  board.  Forms  mountain  beds.  Most 
chalk  was  made  chiefly  out  of  the  shells  of  Rhizopods. 

Hydraulic  limestone  (Cement  stone).  An  impure  lime- 
stone affording,  on  burning,  a  quicklime  that  will  make  a 
cement  that  sets  under  water  (p.  459). 

Oolite,  Pisolite.  Oolite  is  a  compact  limestone,  consist- 
ing of  small  round  concretionary  grains,  looking  like  the 
spawn  of  a  fish;  the  name  is  derived  from  the  Greek  oon, 
an  egg.  Pisolite,  a  name  derived  from  pisum,  the  Latin 
for  pea,  differs  from  oolite  in  being  coarser;  the  spherules 
often  have  a  concentric  structure,  and  thus  show  their  con- 
cretionary origin. 

Argentine.  A  white  shining  limestone  consisting  of  la- 
minae a  little  waving,  and  containing  some  silica. 

Fontainebleau  limestone.  This  name  is  applied  to  crys- 
tals of  the  form  shown  in  figure  3,  containing  a  large  pro- 
portion of  sand,  and  occurring  in  groups.  They  were  for- 
merly obtained  at  Fontainebleau,  France,  but  the  locality 
is  exhausted. 

Rock  milk.  White  and  earthy  like  chalk,  but  still  softer, 
and  very  fragile.  Deposited  from  waters  containing  lime 
in  solution.  Rock  meal  is  a  powdery  variety. 

Calcareous  tufa.  Formed  by  deposition  from  waters  like 
rock  milk,  but  more  cellular  or  porous  and  not  so  soft. 

Stalactite,  Stalagmite.  The  name  stalactite  is  explained 
on  page  60.  The  deposits  of  the  same  origin  that  cover 
the  floors  of  caverns  are  called  stalagmite.  They  generally 
consist  of  differently  colored  layers,  and  appear  banded  or 
striped  when  broken.  The  so-called  "Gibraltar  rock"  is 
stalagmite  from  a  cavern  in  the  rock  of  Gibraltar. 

Thinolite.  Calcite  pseudomorphs,  of  prismatic  and 
pyramidal  forms,  abundant  in  thick  deposits  in  the  basins 
of  old  lakes  over  the  Great  Basin  west  and  southwest  of  the 
Great  Salt  Lake. 

Travertine.  Deposits  from  calcareous  waters  forming 
thick  beds,  as  in  the  Gardiner  River  region  of  the  Yellow- 
stone Park,  Tivoli  (Tibur  of  the  Romans)  near  Rome, 
where  it  was  early  called  Tiburtine,  and  in  many  other 
regions. 


CALCIUM.  237 

Stinkstone,  Antlir aconite.  Gives  out  a  fetid  odor  when 
struck;  caused  by  certain  bituminous  materials  present  in 
the  rock. 

Diff.  Distinguished  by  being  scratched  easily  with  a 
knife;  its  strong  effervescence  in  dilute  acid;  its  com- 
plete infusibility.  Less  hard  than  aragonite,  unlike  it  also 
in  having1  a  very  distinct  cleavage. 

Obs.  Calcite  occurs  in  fine  crystals  at  Eossie,  N".  Y.,  one 
crystal  from  there,  now  in  the  Peabody  Museum  at  New- 
Haven,  weighing  165  pounds;  in  geodes  of  "dog-tooth 
spar"  in  limestone  at  Lockport,  along  with  gypsum  and 
pearl  spar;  at  Leyden  and  Lowville,  N.  Y;  at  Bergen  Hill, 
N.  J.,  in  beautiful  wine-yellow  crystals  in  amygdaloidal 
cavities ;  at  the  Lake  Superior  copper-mines ;  and  else- 
where. Argentine  occurs  near  Williamsburg  and  South- 
ampton, Mass.  Rock  milk  covers  the  sides  of  a  cave  at 
Watertown,  N.  Y.,  and  is  now  forming.  Stalactites  of 
great  beauty  occur  in  Luray,  Weir's,  and  other  caves  in  Vir- 
ginia and  in  the  Western  States.  Clialk  occurs  in  England 
and  Europe;  also  in  Western  Kansas.  Granular  limestones 
are  common  in  the  Eastern  and  Atlantic  States,  and  com- 
pact limestones  in  the  Middle  and  Western  States,  and 
some  beds  of  the  former  afford  excellent  marble  for  building 
and  some  of  good  quality  for  statuary. 

In  the  state  of  quicklime,  it  is  mixed  with  water  and  sand 
to  make  "  mortar;"  a  calcium  hydrate  results  which  becomes 
slowly  carbonated  through  carbonic  acid  in  the  atmosphere. 
See  further  the  chapter  on  Rocks. 

Aragonite. 

Orthorhombic ;  I f\I  =116°  10'.  In  rhombic  prisms; 
usually  in  compound  crystals  having  the  form  of  a  hexag- 
onal prism,  with  uneven  or  striated  sides;  or  in  stellated 
forms  consisting  of  two  or  three  flat  crystals  crossing  one 
another.  Transverse  sections  of  some  of  the  compound 
crystals  are  shown  in  Figs.  1  to  4.  Cleavage  parallel  to  7, 
not  very  distinct.  Also  in  globular  and  coralloidal  shapes; 
also  in  fibrous  seams  in  rocks. 

Color  white,  or  with  light  tinges  of  gray,  yellow,  green, 
and  violet.  Lustre  vitreous.  Transparent  to  translucent. 
H.  =  3-5-4.  G.  =  2-93-2-936. 

Composition.  Same  as  for  calcite;  and  B.B.  with  acids 
the  same,  except  that  it  falls  to  powder  readily  when  heated. 


238 


DESCRIPTIONS   OF   MINERALS. 


Diff.  Distinguished  from  calcite  by  the  absence  of  the 
cleavage  of  the  latter,  as  well  as  the  crystalline  form;  also 
by  its  higher  specific  gravity. 

Obs.  Aragonite  occurs  mostly  in  gypsum  beds  and  in 
connection  with  iron  ores;  also  in  basalt  and  other  rocks. 


2. 


3. 


The  coralloidal  forms  are  found  in  iron  ore  beds,  and  are 
called  Flos  f err i ,  flowers  of  iron.  They  look  like  a  loosely 
intertwined  or  tangled  white  cord. 

The  flos-ferri  variety  occurs  at  Lockport  with  gypsum ; 
at  Edenville,  at  the  Parish  ore  bed  in  Rossie,  N.  Y.,  and 
in  Chester  Co.,  Pa.  Aragon  in  Spain  affords  six-sided 
prisms,  associated  with  gypsum;  hence  the  name  of  the 
species.  Also  at  Bilin,  in  Bohemia;  Tarnowitz,  in  Silesia ; 
and  other  places. 

Dolomite. — Calcium- Magnesium  Carbonate.    Magnesian  Limestone. 

Rhombohedral;  Rf\R  =  106°  15'.    Cleavage  perfect  par- 
allel to  R.    Faces  of  rhombohedrons  sometimes 
curved,  as  in  the  annexed  figure.     Often  gran- 
ular and  massive,  constituting  extensive  beds. 
Color   white,    or   tinged   with  yellow,  red, 
green,  brown,  and  sometimes  black.  Lustre  vit- 
reous or  pearly.     Nearly  transparent  to  trans- 
lucent.    Brittle.     H.  =  3'5-4.     G.  =  2-8-2-9. 

Composition.  -JCa|Mg03C  (or  (iCaiMg)O  +  C02)  = 
Calcium  carbonate  54*35,  magnesium  carbonate  45 '65  = 
100.  Some  iron  or  manganese  is  often  present,  replacing 
part  of  the  magnesium  or  calcium.  Iron-bearing  varieties 
become  brown  on  exposure,  and  the  manganese-bearing, 
black,  yielding  as  the  ultimate  result  generally  limonite, 
and  oxide  of  manganese. 

The  principal  varieties  of  this  species  are  as  follows: 


CALCIUM.  239 

Dolomite.  "White,  crystalline  granular,  often  not  distin- 
guishable in  external  characters  from  granular  limestone. 

Pearl  spar.    In  pearly  rhombohedrons  with  curved  faces. 

Rhomb  spar,  Brown  spar.  In  rhombohedrons,  which 
become  brown  on  exposure,  owing  to  their  containing  1  to 
10  per  cent,  of  oxide  of  iron  or  manganese. 

A  cobaltiferous  variety  has  a  red  tint.  A  white  compact 
siliceous  variety  has  been  called  Gurhofite.  Some  hydraulic 
limestones  are  dolomite. 

Diff.  Distinctive  characters  nearly  the  same  as  for  cal- 
cite.  It  is  harder  than  that  species,  and  differs  in  the 
angles  of  its  crystals,  and  effervesces  in  acids  very  feebly, 
unless  heated;  but  chemical  analysis  is  often  required  to 
distinguish  them. 

Obs.  Common  as  marble  in  western  New  England  and 
southeastern  New  York,  and  constitutes  much  of  that  used 
for  building;  and  the  uncrystalline  constitutes  many  of  the 
limestones  of  New  York  and  the  States  farther  west  arid 
south.  Crystallized  specimens  have  been  obtained  at  the 
Quarantine,  Eichmond  Co.,  N.  Y.;  large  at  Brewster, 
N.  Y.,  and  Alexander  Co.,  N.  C. ;  rhomb  spar  occurs  in  talc, 
at  Smithfield,  R.  I.;  Marlboro',  Vt.;  Middlefield,  Mass.; 
pearl  spar  in  crystals  of  the  above  form  at  Lockport,  Ni- 
agara Falls,  Rochester,  Glen's  Falls;  gurhofite  on  Hustis's 
farm,  Phillipstown,  N.  Y. 

Dolomite  was  named  in  honor  of  the  geologist  and  trav- 
eller Dolomieu. 

Burns  to  quicklime  like  calcite.  The  white  massive 
variety  is  used  extensively  as  marble.  The  magnesian  lime 
has  been  supposed  to  injure  soils;  but  this  is  believed  not 
to  be  the  case  if  it  is  air-slaked  before  being  used.  It  is 
employed  in  England  in  the  manufacture  of  Epsom  salts  or 
magnesium  sulphate. 

Ankerite.  Resembles  brown  spar,  and,  like  that,  becomes  brown 
on  exposure.  Rf\R  =  106°  12'.  A  calcium-magnesium  iron-manga- 
nese carbonate.  The  Styrian  iron  ore  beds  of  Saltzburg  are  some  of 
its  foreign  localities.  Occurs  in  Nova  Scotia;  in  quartz  veins  in 
western  New  Hampshire;  Quebec,  Canada,  etc.  Parankerite  is  a 
variety  of  it. 

Hydrodolomite.  A  calcium-magnesium  carbonate  containing  water. 
Pennite  from  Texas,  Pa.,  is  similar. 

Whewellite.  Calcium  oxalatc.  In  monoclinic  crystals,  England  ; 
coal-bed  near  Dresden. 

Thaumasite.    Mixture  of  carbonate  and  sulphate.     Sweden. 


240 


DESCRIPTIONS   OF  MINERALS. 


BARIUM  AND  STRONTIUM. 

Barium  and  strontium  occur  in  nature  only  in  anhydrous 
ternary  compounds  of  the  following  kinds:  sulphate,  car- 
bonate, silicate;  and  in  silicates  only  in  combination  with 
other  basic  elements.  The  species  are  characterized  by  high 
specific  gravity,  ranging  from  3  '5  to  4*8.  Strontium  gives 
a  red  color  to  the  blowpipe  flame;  and  barium,  if  strontium 
and  other  basic  elements  are  absent,  a  characteristic  green 
color. 


Barite.  —  Heavy  Spar.    Barytes.    Barium  Sulphate. 


Orthorhombic ; 
0  A  H  =  127°  18', 


08' 


I  A  7=101°   40';    0A#  =  1 

Forms  as  in  figures.  Cleavage  1,0, 
perfect.  Massive  varieties  often 
coarse  lamellar;  also  columnar, 
fibrous,  granular,  and  compact. 
Color  white,  sometimes  tinged 
yellow,  red,  brown,  blue,  or  dark 
brown.  Lustre  vitreous;  some- 
times pearly.  Transparent  or 
translucent.  II.  =  2  '5-3  '5.  G-. 
=  4  '3-4  '7;  4-48  of  pure  crystals. 
Composition.  Ba04S  (or  BaO 
-f  SOJ  =  Sulphur  trioxide  34'3, 
baryta  65  '7  =  100.  Strontium 
and  calcite  are  sometimes  pres- 
ent replacing  a  little  barium. 
B.B.  fuses  to  a  bead  which  reacts  alkaline;  imparts  a  green 
color  to  the  flame.  After  fusion  with  soda  in  the  reducing 
flame  on  coal,  if  placed  on  a  silver  coin  and  moistened,  it 
produces  a  black  stain,  due  to  sulphur. 

Diff.  Distinguished  by  its  specific  gravity,  the  inaction 
of  acids,  and  its  hardness. 

Often  present  in  mineral  veins  as  the  gangue  of  the  ore. 
Occurs  in  this  way,  and  also  by  itself,  at  Cheshire,  Ct.; 
Hatfield,  Mass.  ;  Rossie  and  Hammond,  N.  Y.  ;  Perkiomen, 
Pa.,  and  the  lead-mines  of  the  Mississippi  Valley.  Sco- 
harie,  and  Pillar  Point  near  Sackett's  Harbor,  are  other 
localities;  also  near  Fredericksburg,  Marion,  and  Irvington, 
Va.;  N.  Scotia,  etc. 

"Barytes,"  or  barlte,  is  ground  up  and  used  to  adulterate 


BARIUM   AND   STRONTIUM.  241 

white  lead.  When  white  lead  is  mixed  in  equal  parts  with 
it,  it  is  sometimes -called  Venice  white,  and  another  quality 
with  twice  its  weight  of  barite  is  called  Hamburg  white, 
and  another,  one-fourth  white  lead,  is  called  Dutch  white. 
When  the  material  is  very  white,  a  proportion  of  it  gives 
greater  opacity  to  the  color,  and  protects  the  lead  from 
being  speedily  blackened  by  sulphurous  vapors;  and  these 
mixtures  are  therefore  preferred  for  certain  kinds  of  paint- 
ing. 20,000  tons  are  ground  .up  annually  in  the  U.  States. 

Dreelite.    A  barium-calcium  sulphate.    Bcaujeu,  France. 


Witherite.— Barium  Carbonate. 


1. 


Orthorhombic ;  /A/=  118°  30'.  Cleavage  imperfect. 
Also  in  globular  or  botryoidal  forms;  often  massive,  and 
either  fibrous  or  granular.  Color 
yellowish  or  grayish  white  to  white 
when  in  crystals.  Translucent  to 
transparent.  Lustre  a  little  resin- 
ous when  massive.  H.  =  3-4.  G. 
=  4-29-4-35.  Brittle. 

Composition.  Ba(X,C  (or  BaO 
-f  C02)  =  Carbon  dioxide  22-3, 
baryta  77  -7  =  100.  B.B.  decrepi- 
tates; fuses  easily,  tinging  the 
flame  green,  to  a  translucent  glob- 
ule, which  becomes  opaque  on 
cooling,  and  colors  moistened  tur- 
meric paper  red.  Effervesces  in 
hydrochloric  acid. 

Diff.  Distinguished,  by  its  specific  gravity  and  fusibility, 
from  calcite  and  aragonite;  by  its  action  with  acids,  from 
allied  minerals  that  are  not  carbonates  ;  by  yielding  no 
metal,  from  cerussite,  and  by  tingeing  the  flame  green, 
from  strontianite. 

Obs.  Important  foreign  localities  are  Fallowfield  in 
Northumberland  (where  it  is  mined),  Alstonmoor  in  Cum- 
berland, Anglezark  in  Lancashire;  Silesia;  Styria;  Sicily. 
In  the  U.  States,  Lexington,  Ky. 

Witherite,  from  Fallowfield,  is  used  in  chemical  works, 
in  the  manufacture  of  plate-glass,  and  in  France  in  the 
manufacture  of  beet  sugar. 
16 


242  DESCRIPTIONS   OF   MINERALS. 

Barytocalcite.  Barium-calcium  carbonate;  in  monoclinic  crystals; 
white;  H.  =4;  G.  =  3'6-3'7.  Alston-Moor,  England. 

BromUte.  Of  same  composition,  but  orthorhombic.  Bromley  Hill, 
and  Northumberland,  England. 

Nitrobarite.    Barium  nitrate;  soluble.     Chili. 

Celestite. — Strontium  Sulphate. 

Orthorhombic;  I/\I  =103°  30'  to  104°  30'.  Crystals 
rhombic  prisms  or  tabular;  often  long  and  slender.  Cleav- 
age distinct  parallel  with  /. 
Also  columnar  or  fibrous; 
rarely  granular.  Color 
white;  slightly  bluish;  some- 
times clear  white  or  reddish. 
Lustre  vitreous  or  a  little 
pearly.  Transparent  to  translucent.  H.  =  3-3 -5.  G.  = 
3-9-4.  Brittle. 

Composition.  Sr04S  (or  SrO  +  S04)  =  Sulphur  trioxide 
43  '6,  strontia  56*4  =  100.  B.B.  decrepitates  and  fuses, 
tingeing  the  flame  bright  red,  to  a  milk-white  globule,  giv- 
ing an  alkaline  reaction.  With  soda  on  coal  fuses  to  a  mass 
which  when  moistened  blackens  silver. 

Diff.  Differs  from  barite,  by  the  bright  red  color  of  the 
flame  B.B.,  and  its  less  specific  gravity;  and  from  the  car- 
bonates, by  not  effervescing  with  acids. 

Obs.  Found  in  beds  of  sandstone  or  limestone,  and  also 
with  gypsum,  rock  salt,  and  clay.  Bluish  tabular  and 
prismatic  crystals,  at  Strontian  Island,  Lake  Erie;  Schoharie, 
Lockport,  and  Rossie,  N.  Y. ;  handsome  fibrous  at  Frank- 
tow^,  Huntingdon  County,  and  BelFs  Mills,  Blair  Co.,  Pa. 
Sicily  affords  fine  crystallizations  associated  with  sulphur. 

The  pale  sky-blue  tint,  so  common  with  the  mineral,  gave 
origin  to  the  name  celestite. 

Used  in  the  arts  for  making  nitrate  of  strontia,  which  is 
employed  for  producing  a  red  color  in  fireworks. 

Strontianite. — Stront  ium  Carbonate. 

Orthorhombic;  /A/=  117°  19'.  Cleavage  parallel  to  /, 
nearly  perfect.  Also  fibrous  and  granular;  sometimes  in 
globular  shapes,  radiated  within. 

Color  pale  greenish  white;  also  white,  gray,  and  yellow- 
ish brown.  Lustre  vitreous,  or  somewhat  resinous.  Trans- 


POTASSIUM    AND   SODIUM.  243 

parent  to  translucent.  H.  =  3 '5-4.  G.  =  3 -6-3 '72. 
Brittle. 

Composition.  Sr03C  (or  SrO  +  C02)  =  Carbon  dioxide 
29 '7,  strontia  70*3  —  100.  Some  strontium  often  replaced 
by  calcium.  B.B.  swells,  throws  out  little  sprouts,  but  does 
not  fuse.  Colors  the  flame  bright  red;  after  heating,  pos- 
sesses an  alkaline  reaction.  Effervesces  in  cold  dilute  acid; 
sulphuric  acid  gives  a  precipitate  of  strontium  sulphate. 

Diff.  Its  effervescence  with  acids  distinguishes  it  from 
minerals  that  are  not  carbonates;  the  color  of  the  flame 
B.B.,  from  witherite  and  other  carbonates;  calcium  salts 
also  give  a  red  color  to  the  flame,  but  the  shade  is  yellowish 
and  less  brilliant. 

Obs.  In  limestone  at  Schoharie,  N".  Y.,  both  in  crystals, 
fibrous,  and  massive;  in  Jefferson  Co.,  N.  Y.;  Mifflin  Co., 
Pa.  Strontian  in  Argyleshire,  England,  was  the  first 
locality  known,  and  gave  the  name  to  the  mineral,  whence 
the  metal  strontium ;  occurs  there,  with  galenite,  in  stellated 
and  fibrous  groups,  and  in  crystals. 

Used  for  preparing  the  strontium  nitrate. 


POTASSIUM  AND  SODIUM. 

Potassium  and  sodium  occur  in  nature  in  the  state  of 
chloride,  sulphate,  nitrate,  and  carbonate,  and  are  constitu- 
ents in  many  silicates. 

Sylvite.— Potassium  Chloride. 

Isometric;  crystals  often  cubes  with  octahedral  planes 
(Fig.  8,  p.  19).  White  or  colorless.  Lustre  vitreous. 
Taste  nearly  that  of  common  salt.  H.  =  2.  G.  =  1*9-2. 

Composition.  KC1  =  Chlorine  47*5,  potassium  52 -5  = 
100.  From  Vesuvius  and  Stassfurt. 

Other  potassium  chlorides  containing  iron,  p.  200. 

Halite.— Common  Salt.     Sodium  Chloride. 

Isometric.  In  cubes,  and  related  forms.  Sometimes  in 
shallow  concave  hopper-shaped  crystals  formed  by  the  en- 
largement at  the  margin  of  a  floating  crystal.  Cleavage 
cubic,  perfect. 

Color  white  or  grayish,  sometimes  rose-red,  yellow,  and 
of  amethystine  tints.  Taste  saline.  H.  =2.  6.  =  2*257. 


244  DESCRIPTIONS   OF   MINERALS. 

Composition.  NaCl  =  Chlorine  60 '7,  sodium  39*3  =  100. 
Crackles  or  decrepitates  when  heated;  fuses  easily,  coloring 
tne  flame  deep  yellow.  A  variety  from  Chili  (Huantajayite) 
contains  11  p.  c.  of  silver  chloride. 

Diff.  Distinguished  by  its  solubility  and  taste. 

Obs.  Occurs  in  extensive  but  irregular  beds,  usually  asso- 
ciated with  gypsum,  anhydrite,  and  clays  or  sandstone. 
Exists  in  formations  of  all  ages,  from  the  Silurian  to  the 
present  time.  Found  in  the  Pyrenees,  in  the  valley  of 
Cardona,  and  elsewhere,  forming  hills  300  to  400  feet  high; 
in  Poland  and  Wieliczka;  at  Hall  in  the  Tyrol,  and  along 
a  range  through  Reichenthal  in  Bavaria,  Hallein  in  Salz- 
burg, Hallstadt,  Ischl  and  Ebensee  in  Upper  Austria,  and 
Aussee  in  Styria;  in  Hungary  at  Marmoros  and  elsewhere; 
in  Transylvania,  Wallachia,  Galicia,  and  Upper  Silesia;  at 
Vic  and  Dieuze  in  France;  at  Bex  in  Switzerland;  in 
Cheshire,  England;  in  Northern  Africa  in  vast  quantities, 
forming  hills  and  extended  plains;  in  Northern  Persia  at 
Tin1  is;  in  India  in  the  province  of  Lahore  and  in  the  valley 
of  Cashmere;  in  China  and  Asiatic  Russia;  in  South  Amer- 
ica, in  Peru  and  the  Cordilleras  of  New  Granada. 

Among  the  most  remarkable  deposits  are  those  of  Poland 
and  Hungary.  The  former,  near  Cracow,  have  been  worked 
since  the  year  1251,  and  it  is  calculated  that  there  is  still 
enough  salt  remaining  to  supply  the  whole  world  for  many 
centuries.  Its  deep  subterranean  regions  are  excavated  into 
houses,  chapels  and  other  ornamental  forms,  the  roof  being 
supported  by  pillars  of  salt;  and  when  illuminated  by  lamps 
and  torches  they  are  objects  of  great  splendor. 

The  salt  is  often  impure  with  clay,  and  is  purified  by  dis- 
solving it  in  large  chambers,  drawing  it  off  after  it  has 
settled,  and  evaporating  it  again.  The  salt  of  Norwich  (in 
Cheshire)  is  in  masses  5  to  8  feet  in  diameter,  which  are 
nearly  pure,  and  it  is  prepared  for  use  by  crushing  it  be- 
tween rollers. 

In  North  America,  beds  of  rock  salt  exist  at  Goderich  in 
Canada;  at  Wyoming  and  other  places  in  western  New 
York  (reached  by  boring  to  a  depth  of  1000  feet  or  more); 
in  West  Virginia  on  the  Great  Kanawha,  etc. ;  extensively 
at  Petite  Anse,  La.,  where  it  underlies  144  acres;  in  Nevada, 
Montana,  Utah,  Wyoming,  Idaho,  Dakota,  New  Mexico, 
California;  in  the  Salmon  River  Mts.,  Oregon. 

Brine  springs  also  proceed  from  rocks  of  various  ages ; 


POTASSIUM   AND   SODIUM.  245 

and  often  they  are  indications  of  deep-seated  beds  of  rock 
salt. 

The  salt  of  western  New  York,,  and  Goderich,  Canada, 
is  of  the  Salina  period  of  the  Upper  Silurian;  the  brine 
springs  of  Michigan,  Ohio,  and  Kanawha,  from  shales  and 
marlytes  of  the  Carboniferous  age;  those  of  the  salt  beds  of 
Norwich,  England,  in  magnesian  limestone  of  the  Permian; 
those  of  the  Vosges  and  of  Salzburg,  Ischl,  and  the  neigh- 
boring regions,  in  marly  sandstone  of  the  Triassic;  those  of 
Bex,  in  Switzerland,  in  the  Lias  formation;  that  of  Wie- 
liczka,  Poland,  and  the  Pyrenees,  in  the  Cretaceous  or  Chalk 
formation;  that  of  Catalonia,  in  the  Tertiary;  that  of 
Louisiana,  in  the  Quaternary,  and  large  deposits  are  still 
more  recent ;  and,  besides,  there  are  lakes  that  are  now 
evaporating  and  producing  salt  depositions. 

Vast  lakes  of  salt  water  exist  in  many  parts  of  the  world. 
The  Great  Salt  Lake  of  Utah  has  an  area  of  2000  square 
miles,  and  is  remarkable  for  its  extent,  considering  that  it 
is  situated  at  an  elevation  of  4200  feet  above  the  sea.  The 
dry  regions  of  the  Great  Basin  and  of  Southeastern  Cali- 
fornia are  noted  for  salt  licks  and  lakes.  In  Northern 
Africa  large  lakes  as  well  as  hills  of  salt  abound,  and  the 
deserts  of  this  region  and  Arabia  abound  in  saline  efflores- 
cences. The  Dead  and  Caspian  seas,  and  the  lakes  of 
Khoordistan,  are  salt.  From  20-26  parts  in  a  hundred  of 
the  weight  of  the  water  from  the  Dead  Sea  are  solid  salts, 
of  which  10  parts  are  common  salt.  Over  the  pampas  of 
La  Plata  and  Patagonia  there  are  many  ponds  and  lakes  of 
salt  water. 

The  greater  part  of  the  salt  made,  in  Eastern  North 
America  is  obtained  by  evaporation  from  salt  springs,  and 
Michigan  and  New  York  are  the  chief  sources.  At  the 
best  springs  at  Syracuse,  N.  Y.,  a  bushel  of  salt  is  obtained 
from  every  40  gallons.  But  the  discovery  of  rock  salt  at 
Wyoming,  and  elsewhere  west  of  Syracuse,  may  make  the 
brines  of  New  York  of  comparatively  little  value. 

The  process  of  evaporation  under  the  heat  of  the  sun  is 
extensively  employed  in  hot  climates  for  making  salt  from 
sea  water,  which  affords  a  bushel  for  every  300  or  350  gal- 
lons. For  this  purpose  a  number  of  large  shallow  basins 
are  made  adjoining  the  sea;  they  have  a  smooth  bottom  of 
clay,  and  all  communicate  with  one  another.  The  water  is 
let  in  at  high  tide  and  then  shut  off  for  the  evaporation  to 


V 


246  DESCRIPTIONS   OF  MINERALS.      . 

go  on.     This  is  the  simplest  mode,  and  is  used  even  in  un- 
civilized countries,  as  among  the  Pacific  Islands. 

The  salt  product  of  the  U.  States  in  1884  was  about 
32,575,000  bushels  (or  a  fifth  of  this  number  of  barrels); 
of  which  15,810,000  was  from  Michigan,  8,940,000  from 
New  York;  1,750,000  from  Ohio,  and  1,600,000  from  W. 
Virginia.  In  1885,  it  was  35,200,000  bushels. 

Mirabilite. — Glauber  Salt.     Hydrous  Sodium  Sulphate. 

Monoclinic.  (Figure,  p.  42. )  In  efflorescent  crusts  of  a 
white  or  yellowish-white  color;  also  in  many  mineral  waters. 
Taste  cool,  then  feebly  saline  and  bitter. 

Composition.  Na204S  -f  10  aq  (or  Na20  -f  SO,  +  10  aq) 
=  Sulphur  trioxide  24'8,  soda  19 '3,  water  55 -9  =  100. 

Diff.  Distinguished  from  Epsom  salt,  for  which  it  is 
sometimes  mistaken,  by  its  coarse  crystals,  and  the  yellow 
color  it  gives  to  the  blowpipe  flame. 

Manufactured  from  common  salt,  its  production  being 
one  stage  in  the  manufacture  of  sodium  carbonate. 

Obs.  From  Aussee,  Austria;  Sicily;  Tarapaca;  etc.;  on 
Hawaii,  in  a  cave  at  Kailua,  where  it  is  now  forming ;  in 
efflorescences  on  the  limestone  below  Genesee  Falls,  near 
Rochester,  N.  Y. ;  Sweetwater  Valley,  Wyoming;  Morrison, 
Cal. ;  New  Mexico. 

The  artificial  salt  was  first  made  by  a  German  chemist 
by  the  name  of  Glauber. 

Aphthitdlite  (Arcanite).  Potassium  sulphate,  K2O4S  —  Sulphate  tri- 
oxide 45-9,  potash  541  =  100.  Vesuvius. 

Misenite.     Hydrous  potassium  sulphate.     A  cavern  near  Misene. 

Thenardite.  Sodium  sulphate,  Na2O4S  =  Sulphur  trioxide  43 '7, 
soda  56'3  =  100.  Spain;  Bolivia;  Tarapaca,  in  Peru;  Slate  Range, 
San  Bernardino  Co.,  Cal.;  in  Nevada;  on  the  Rio  Verde,  Arizona. 

Olauberite.  Sodium-calcium  sulphate;  in  monoclinic  crystals. 
Villa  Rubia,  in  New  Castile;  Aussee,  Austria;  and  other  salt  beds. 

Syngenite.     Hydrous  potassium-calcium  sulphate.    East  Galicia. 

Wattemllite.  Hydrous  sodium  -  potassium  -  calcium  sulphate. 
Bavaria. 

Tarapacaite.    Potassium  chromate;  yellow.    Tarapaca. 

Borax. — Hydrous  Sodium  Biborate.     Tinkal. 

Monoclinic;  I/\I=  87°.  Cleavage  parallel  with  i-i  per- 
fect. Crystals  white  or  colorless;  often  transparent;  lustre 
vitreous.  H.  =  2-2 '5.  G.  =  1-716.  Taste  sweetish-alka- 
line. 


POTASSIUM   AND   SODIUM.  247 

Composition.  Na207B4  -f  10  aq  (or  Na20 -{- 2B203 -f 
10  aq)  —  Boron  trioxide  36-6,  soda  16  '2,  water  47 '2  =  100. 
B.B.  swells  up  to  many  times  its  bulk,  becomes  opaque 
white,  and  finally  fuses  to  a  glassy  globule. 

Obs.  Originally  brought  from  a  salt  lake  in  Thibet,  where 
it  is  dug  in  masses  from  the  edges  and  shallow  parts  of  the 
lakes ;  deposition  is  now  going  on.  Crude  borax  was 
formerly  sent  to  Europe  under  the  name  of  tinkal, 
and  there  purified  for  the  arts.  Also  found  in  Asiatic 
Turkey,  Peru,  and  Ceylon.  Has  been  extensively  made 
from  the  boracic  acid  of  the  Tuscan  lagoons  by  the  reac- 
tion of  this  acid  on  sodium  carbonate.  The  borax  of  com- 
merce is  in  part  made  from  ulexite  and  lime-borate  (p.  231). 

Occurs  under  like  circumstances  in  California  and 
Nevada,  or  is  manufactured  from  other  borates  in  solution. 
Localities  in  California  are  Clear  Lake  and  vicinity; 
near  Walker's  Pass,  Sierra  Nevada;  at  Mono  and  Owens 
Lakes,  and  at  Death  Valley,  in  Inyo  Co.,  Cal.,  near  the 
borders  of  Nevada;  in  the  Slate  Range  Marsh,  in  San 
Bernardino  Co.,  Cal.;  in  Churchill  Co.,  Nev.;  at  Little 
Salt  Lake,  near  Ragtown,  on  the  Pacific  Railroad,  and  in 
Esmeralda  Co.,  at  Columbus,  TeeFs  and  Rhodes'  Marshes, 
and  in  Fish  Lake  Valley.  The  large  deposits  of  "  priceite"  in 
Southern  Oregon,  and  of  ulexite  (p.  231)  in  the  "  Cane 
Spring  District,"  20  miles  west  of  San  Bernardino,  and  at 
the  Columbus  Marsh,  are  other  sources  of  borax.  The 
amount  of  California  and  Nevada  borax  produced  in  1876 
was  5,180,910lbs.;  in  1880,  3,860,748  Ibs.;  in  1882,  4,236,- 
291  Ibs.;  in  1884,  7,000,000  Ibs.;  in  1885,  8,000,000  Ibs. 

Tincalconite.    Efflorescence  on  borax.    California. 


/ 


Nitre.— Potassium  Nitrate. 


Orthorhombic ;  /A/=118°  50'.  In  modified  right 
rhombic  prisms.  Usually  in  thin,  white  crusts,  and  in 
acicular  crystals.  Taste  saline  and  cooling.  H.  =  2.  G. 
=  1-97. 

Composition.  K03N  (or  K20  -f-  N206)  =  Nitrogen  pen- 
toxide  (N205)  53*4,  potash  46*6.  Burns  vividly  on  a  live 
coal. 

Dif.  Distinguished  by  the  taste,  and  vivid  action  on  a 
live  coal;  and  from  sodium  nitrate,  which  it  most  resembles, 
by  not  becoming  liquid  on  exposure  to  the  air. 


248  DESCRIPTIONS   OF   MINERALS. 

Ops.  Occurs  in  many  of  the  caverns  of  Kentucky  and 
Indiana,  etc.,  scattered  through  the  earth  that  forms  the 
floor  of  caves,  and  in  many  of  the  States  and  Territories  of 
the  far  West.  In  procuring  it,  the  earth  is  lixiviated,  and 
the  lye,  when  evaporated,  yields  the  nitre. 

India  is  its  most  abundant  locality,  where  it  is  obtained 
largely  for  exportation.  This  salt  forms  on  the  ground  in 
the  hot  weather  succeeding  copious  rains,  and  appears  in 
silky  tufts  or  efflorescences;  these  are  brushed  up  by  a  kind 
of  broom,  lixiviated,  and  after  settling,  evaporated  and 
crystallized.  In  France,  Germany,  Sweden,  Hungary,  and 
other  countries,  there  are  artificial  arrangements  called 
iiitriaries  or  nitre  beds,  from  which  nitre  is  obtained  by 
the  decomposition  mostly  of  the  nitrates  of  lime  and  mag- 
nesia which  form  in  these  beds.  Refuse  animal  and  vege- 
table matter  putrefied  in  contact  with  calcareous  soils  pro- 
duces nitrate  of  lime,  which  affords  the  nitre  by  reaction 
with  carbonate  of  potash.  Old  plaster  lixiviated  affords 
about  5  per  cent.  This  last  method  is  much  used  in  France. 
Nitrification  takes  place  through  the  agency  of  a  peculiar 
kind  of  microscopic  plant,  related  to  the  bacteria. 

Nitre,  called  also  saltpetre,  is  employed  in  making  gun- 
powder, forming  75  to  78  per  cent,  in  shooting  powder,  and 
62  in  mining  powder.  The  other  materials  are  sulphur  (10 
per  cent,  for  shooting  powder  to  20  for  mining)  and  char- 
coal (12  to  14  for  shooting  powder  and  18  for  mining).  It 
is  also  extensively  used  in  the  manufacture  of  nitric  and 
sulphuric  acids;  also  for  pyrotechnic  purposes,  fulminating 
powders,  and  sparingly  in  medicine. 

Nitratine.— Soda  Nitre.     Sodium  Nitrate.     Cubic  Nitre. 

Rhombohedral ;  R  :  R=  106°  33'.  Also  in  crusts  or 
efflorescences,  of  white,  grayish,  and  brownish  colors.  Taste 
cooling.  Soluble  and  very  deliquescent. 

Composition.  NaOsN  (or  Na20  +  NaOB)  =  Nitrogen  pen- 
toxide  63  "5,  soda  36*5  =  100.  Burns  vividly  on  coal,  with 
a  yellow  light. 

Diff.  Resembles  nitre  (saltpetre),  but  deliquesces,  and 
gives  a  deep  yellow  light  when  burning. 

Obs.  In  the  district  of  Tarapaca,  Northern  Chili,  it 
covers  the  dry  Pampa  for  an  extent  of  forty  leagues,  mixed 
with  gypsum,  common  salt,  glauber  salt,  and  remains  of 


AMMONIUM.  249 

recent  shells;  in  Humboldt  Co.,  Nev.;  New  Mexico;   near 
Calico,  Cal. 

Used  extensively  in  the  manufacture  of  nitric  acid;  also 
in  making  nitre  by  replacing  the  sodium  by  potassium. 

Natron. — Hydrous  Sodium  Carbonate.    Carbonate  of  Soda. 

Monoclinic.  Generally  in  white  efflorescent  crusts,  some- 
times yellowish  or  grayish.  Taste  alkaline.  Effloresces  on 
exposure,  the  surface  becoming  white  and  pulverulent. 

Composition.  NaaO,C  +  10  aq  (or  ]STa20  +  CO,  +  10  aq) 
=  Carbon  dioxide  26«7,  soda  18'8,  water  54-5  =  100. 
Effervesces  strongly  with  acids. 

Diff.  Distinguished  from  other  soda  salts  by  effervescing, 
and  from  trona,  by  efflorescing  on  exposure. 

Obs.  Found  in  solution  in  certain  waters,  from  which  it 
is  crystallized  in  efflorescences  by  evaporation.  Abundant 
in  the  soda  lakes  of  Egypt;  also  in  lakes  at  Debreczin,  in 
Hungary;  in  the  alkali  flats  of  the  Great  Basin,  abundant; 
in  Carbon  Co. ,  Wyoming,  where  are  over  100  soda  lakes, 
20  to  300  acres  in  area,  and  15  to  45  feet  deep. 

This  salt  (but  the  artificially  prepared)  is  extensively 
used  in  the  manufacture  of  soap  and  glass,  and  for  many 
other  purposes. 

Trona.  Hydrous  sodium  sesquicarbonate.  Occurs  in  the  province 
of  Suckenna,  in  Africa,  between  Tripoli  and  Fezzan,  constituting  a 
fibrous  layer  an  inch  thick  beneath  the  soil;  abundant  at  a  lake  in 
Maracaibo,  48  miles  from  Mendoza;  an  extensive  bed  in  Churchill 
Co.,  Nev. 

'ihermonatrite.     Hydrous  sodium  carbonate,  NaaOaC  -f-  aq. 

Qay-Lussite.  White;  brittle ;  monoclinic;  composition  ^Na^CaOa 
C  -h  2£  aq.  Lagunilla,  in  Maracaibo;  Little  Salt  Lake,  near  Kagtown, 
Nev. 

Hanksite.  Sodium  sulphato-carbonate  in  hexagonal  crystals. 
California. 

AMMONIUM. 

The  salts  of  ammonia  are  more  or  less  soluble  in  water, 
and  are  entirely  and  easily  volatilized  before  the  blowpipe. 
When  treated  with  caustic  lime  or  potassa,  ammonia  is  lib- 
erated, and  is  recognized  by  its  odor  and  the  reaction  of  the 
vapors  on  test  papers. 

Salmiak. — Sal  Ammoniac,  Ammonium  Chloride. 
In  white  crusts  or  efflorescences,  often  yellowish  or  gray. 


250  DESCRIPTIONS   OF  MINERALS. 

Translucent — opaque.  Taste  saline  and  pungent.  Soluble 
in  three  parts  of  water. 

Composition.  NH4C1  =  Chlorine  66*3,  ammonium  33 '7 
=  100.  Gives  off  the  odor  of  ammonia  when  powdered  and 
mixed  with  quicklime. 

Obs.  Occurs  in  many  volcanic  regions,  as  at  Etna,  Vesu- 
vius, and  the  Sandwich  Islands,  where  it  is  a  product  of 
volcanic  action.  Occasionally  found  about  ignited  coal 
seams. 

Sal  ammoniac  is  one  of  the  products  found  in  the  soot 
and  smoke  of  both  wood  and  coal  fires.  The  sal  ammoniac 
of  commerce  was  formerly  manufactured  from  animal 
matter  or  coal  soot.  In  Egypt,  whence  the  greater  part  of 
this  salt  was  obtained,  the  fires  of  the  peasantry  are  made 
of  the  dung  of  camels;  and  the  soot  which  contains  a  con- 
siderable portion  of  the  ammoniacal  salt  is  preserved  and 
carried  in  bags  to  the  works,  where  it  is  obtained  by  subli- 
mation. But  the  ammoniacal  liquor  of  the  gas-works 
affords  crude  sulphate  of  ammonium,  and  from  it,  the  sal 
ammoniac  of  commerce  is  now  obtained  by  subliming  a  mix- 
ture of  this  sulphate  with  common  salt  (sodium  chloride). 

A  valuable  article  in  medicine.  Employed  by  tinmen  in 
soldering  to  prevent  the  oxidation  of  copper  surfaces,  and, 
also  in  a  variety  of  metallurgical  operations. 

Mascagmte.  A  hydrous  ammonium  sulphate;  in  mealy  crusts,  of  a 
yellowish  gray  or  lemon-yellow  color;  translucent;  taste  pungent  and 
bitter;  composition  (NH-OaC^S  -f-  H2O  =  Sulphur  tiioxide  53'3,  am- 
monia 22*8,  water  23 '9  ;  easily  soluble  in  water.  Etna;  Vesuvius; 
the  Lipari  Islands;  the  Guanape  Isles,  in  guano.  One  of  the  products 
from  the  combustion  of  anthracite  coal. 

Lecontite.  Hydrous  ammonium-sodium  sulphate.  Near  Comay- 
agua,  Central  America. 

BoussmgauHite,  hydrous  ammonium -magnesium  sulphate.  Tus- 
cany. Hannayite  is  another,  in  triclinic  crystals,  from  guano  in 
Victoria,  with  struvite. 

Struvite.  Hydrous  ammonium-magnesium  phosphate;  in  yellowish 
crystals,  slightly  soluble  in  water.  Found  on  the  site  of  an  old  church 
in  Hamburg,  where  there  had  been  quantities  of  cattle  dung. 

Tschermigite.  An  ammonia  alum.  Tschermig,  Bohemia ;  Utah 
Co.,  Utah. 

Larderellite.  A  white,  tasteless,  ammonium  borate.  Tuscan  la- 
goons. 

Hydrous  ammonium  phosphate  and  Ammonium  bicarbonate  (Tesche- 
macherite]  have  been  detected  in  guano;  also,  Hydrous  sodium-am- 
monium phosphate,  called  Stercorite. 

Cryptohalite.    A  probable  ammonium  fluosilicate.    Vesuvius, 


HYDROGEN — WATER.  251 


HYDROGEN. 

Hydrogen  is  the  basic  constituent  in  hydrochloric  acid, 
and  in  water. 

Hydrochloric  Acid. — Muriatic  Acid,  Hydrogen  Chloride. 

A  gas,  consisting  of  Chlorine  97*26,  hydrogen  2*74  =  100 
=  HC1.  It  has  a  pungent  odor,  and  is  acrid  to  the  skin. 

Rapidly  dissolved  by  water.  Passed  into  a  solution  of 
nitrate  of  silver,  it  produces  a  white  precipitate  (silver 
chloride)  which  soon  blackens  011  exposure.  Passes  off 
whenever  common  salt  is  acted  on  by  sulphuric  acid;  occa- 
sionally formed  about  volcanoes. 

Hydrofluorite.  Hydrofluoric  acid  or  hydrogen  fluoride.  An  -ema- 
nation at  some  eruptions  of  Vesuvius,  as  observed  by  Scacchi. 


WATER. 

Water  (hydrogen  oxide)  is  the  well-known  liquid  of 
streams  and  wells.  The  purest  natural  water  is  obtained  by 
melting  snow,  or  receiving  rain  in  a  clean  glass  vessel;  but 
it  is  absolutely  pure  only  when  procured  by  distillation. 
It  consists  of  hydrogen  1  part  by  weight,  and  oxygen  8 
parts,  or  hydrogen  11*11,  oxygen  88*89  =  100.  It  becomes 
solid  at  32°  Fahrenheit  (or  0  Centigrade),  and  then  crys- 
tallizes, and  constitutes  ice  or  snow.  The  crystals  are  of 
the  hexagonal  system.  Flakes  of  snow  consist  of  a  congeries 
of  minute  crystals,  and  stars,  like  the  figures  on  page  4,  may 
often  be  detected  with  a  glass.  Various  other  allied  forms 
are  also  assumed.  The  rays  meet  at  an  angle  of  60°,  and 
the  branchlets  pass  off  at  the  same  angle  with  perfect  regu- 
larity. The  density  of  water  is  greatest  at  39°  *2  F.;  below 
this  it  expands  as  it  approaches  32°,  and  in  the  state  of  ice 
it  is  only  0'920.  It  boils  at  212°  F.  A  cubic  inch  of  pure 
water  at  62°  F.  and  30  inches  of  the  barometer,  weighs 
252*458  grains,  which  equals  16.386  grams;  and  a  cubic 
foot  of  water  weighs  62*355  pounds  avoirdupois.  A  pint, 
United  States  standard  measure,  holds  just  7342  troy  grains 
of  water,  which  is  little  above  a  pound  avoirdupois  (7000 
grains  troy). 


252  DESCRIPTIONS   OP   MINERALS. 

Water,  as  it  occurs  on  the  earth,  contains  some  atmo- 
spheric air,  without  which  the  best  would  be  unpalatable. 
This  air,  with  some  free  oxygen  also  present,  is  necessary 
to  the  life  of  aquatic  animals.  In  most  spring  water  there 
is  a  minute  proportion  of  salts  of  calcium  (sulphate,  chloride 
or  carbonate),  often  with  a  trace  of  common  salt,  carbonate 
of  magnesium,  and  some  alumina,  iron,  silica,  phosphoric 
acid,  carbonic  acid,  and  certain  vegetable  acids.  These 
impurities  constitute  usually  from  -^  to  10  parts  in  10,000 
parts  by  weight.  The  water  of  Long  Pond,  near  Boston, 
contains  about  ^  a  part  in  10,000;  the  Schuylkill  of  Phila- 
delphia, about  1  part  in  10,000;  the  Croton,  used  in  New, 
York  City,  1  to  1^  parts  in  10,000.  Nitric  acid  is  usually 
found  in  rain-water  combined  with  ammonia;  river-waters 
are  ordinarily  the  purest  of  natural  waters,  unless  they  have 
flowed  through  a  densely  populated  region. 

Sea- water  contains  from  32  to  37  parts  of  solid  substances 
in  solution  in  1000  parts  of  water.  The  largest  amount  in 
the  Atlantic,  36*6  parts,  is  found  under  the  equator,  away 
from  the  land  or  the  vicinity  of  fresh- water  streams;  and 
the  smallest  in  narrow  straits,  as  Dover  Straits,  where  there 
are  only  32 '5  parts.  In  the  Baltic  and  Black  Seas  the  pro- 
portion is  only  one  third  that  in  the  open  ocean.  Of  the 
whole,  one  half  to  two  thirds  is  common  salt  (sodium  chlo- 
ride). The  other  ingredients  are  magnesium  salts. (chloride 
and  sulphate),  amounting  to  four  fifths  of  the  remainder, 
with  sulphate  and  carbonate  of  calcium,  and  traces  of  bro- 
mides, iodides,  phosphates,  borates,  and  fluorides.  The 
water  of  the  British  Channel  affords  water  964'7  parts  in 
1000,  sodium  chloride  27*1,  potassium  chloride  0'8,  mag- 
nesium chloride  3 '7,  magnesium  sulphate  2*30,  calcium 
sulphate  1  -4,  calcium  carbonate  0  -03,  with  some  magnesium 
bromide  and  probably  traces  of  iodides,  fluorides,  phosphates 
and  borates.  The  bitter  taste  of  sea-water  is  owing  to  the 
salts  of  magnesium  present. 

The  waters  of  the  Dead  Sea  contain  200  to  260  parts  of 
solid  matter  in  1000  parts  (or  20  to  26  percent.),  including 
7  to  10  per  cent,  of  common  salt,  the  same  proportion  of 
magnesian  salts,  principally  the  chloride,  2^  to  3|  per  cent, 
of  calcium  carbonate  and  sulphate,  besides  some  bromides 
and  alumina.  The  density  of  these  waters  is  owing  to  this 
large  proportion  of  saline  ingredients. 

Mineral  waters  vary  much  in  constitution.     They  often 


SILICA. 


253 


contain  iron  in  the  state  of  bicarbonate,  like  those  of  Sara- 
toga and  Ballstown,  and  are  then  called  chalybeate  waters, 
Hydrogen  sulphide  is  often  held  in  mineral  waters  and  im- 
parts to  them  its  odor  and  taste;  such  are  the  so-called  sul- 
phur  springs. 

Minute  traces  of  salts  of  zinc,  arsenic,  lead,  copper,  silver, 
antimony,  and  tin  have  been  found  in  some  waters.  What- 
ever is  soluble  in  a  region  through  which  waters  flow  will 
of  course  be  taken  up  by 'them,  and  many  ingredients  are 
soluble  in  minute  proportions  which  are  usually  described 
as  insoluble. 

III.  SILICA  AND  SILICATES. 

1.  SILICA. 

Quartz. 

Rhombohedral ;  jR/\#  =  94°  15'.  Usually  in  six-sided 
prisms,  terminating  in  six-sided  pyramids.  No  cleavage 
apparent,  seldom  even  in  traces;  but  sometimes  obtained 
by  heating  and  plunging  the  crystal  into  cold  water. 


1. 


2. 


3. 


5. 


Sometimes  in  coarse  radiated  forms;  also  coarse  and  fine 
granular  (sandstone-like);  also  compact,  crypto-crystalline 
(flint-like),  either  amorphous,  or  presenting  stalactitic  and 
mammillary  shapes. 

Often  colorless;  sometimes  topaz-yellow,  amethystine, 
rose,  smoky,  or  other  tints;  also  of  various  shades  of  yellow, 
red,  green,  blue,  and  brown  colors  to  black;  in  some  varieties 
the  colors  in  bands,  stripes,  or  clouds.  Of  all  degrees  of 
transparency  to  opaque.  Lustre  vitreous;  of  crystals 
splendent;  of  some  jnassive  forms,  dull,  often  waxy.  H. 
=  7.  G.  =  2-5-2-8;  pure  crystals  2 -65. 

Composition.  SiO,  —  Oxygen  53 '33,  silicon  46 -67  =  100. 
B.B.  infusible  ;  with  soda,  fuses  with  effervescence. 


254  DESCRIPTIONS   OF   MINERALS. 

The  common  mineral  impurities  are  chlorite,  rutile,  asbes- 
tus,  actinolite,  tourmaline,  hematite,  limonite.  Hematite 
(red  iron  oxide)  is  the  usual  red  coloring  matter;  limonite, 
mostly  in  the  state  of  yellow  ochre,  the  yellow  and  brownish 
yellow;  chlorite  and  actinolite  give  a  green  color,  and  an 
oxide  or  silicate  of  nickel,  an  apple-green  tint;  manganese 
an  amethystine;  carbonaceous  matters,  such  as  color  marsh 
waters,  smoke-brown  shades.  Quartz  crystals  often  con- 
tain liquids  in  cavities,  either  water,  petroleum  or  naphtha- 
like  material,  or  liquid  carbon  dioxide  (p.  ).  Chalcedony 
usually  has  more  or  less  of  disseminated  opal;  and  clear 
quartz  is  sometimes  spangled  with  scales  of  mica  or 
rendered  opaline  by  means  of  asbestus.  Flint  or  chert  are 
often  colored  by  mixture  with  the  material  of  the  enclosing 
rock. 

Diff.  Quartz  is  exceedingly  various  in  color  and  form, 
but  may  be  distinguished,  by  (1)  absence  of  true  cleavage; 
(2}  its  hardness;  (3)  its  infusibility  before  the  blowpipe; 
(4)  its  insolubility  with  either  of  the  common  acids;  (5)  its 
effervescence  when  heated  B.B.  with  soda;  and  (6)  when 
crystallized,  by  the  forms  of  its  crystals,  which  are  almost 
always  six-sided  prisms  terminating  in  six-sided  pyramids. 

The  varieties  of  quartz  owe  their  peculiarities  either  to 
crystallization,  mode  of  formation,  or  impurities,  and  they 
fall  naturally  into  three  series. 

I.  The  vitreous  varieties,  distinguished  by  their  glassy 
fracture. 

II.  The  chalcedonic  varieties,  having  a  subvitreous  or  a 
waxy  lustre,  and  generally  translucent. 

III.  The   jaspery   cryptocrystalline    varieties,    having 
barely  a  glimmering  lustre  or  none,  and  opaque. 

I.   VITREOUS  VARIETIES. 

Rock  Crystal.     Pure  pellucid  quartz.     G.  =  2-65. 

To  this  mineral  the  word  crystal  was  first  applied  by  the 
ancients;  it  is  from  the  Greek  Jcrustallos,  meaning  ice. 
The  pure  specimens  are  often  cut  and  used  in  jewelry, 
under  the  name  of  "white  stone."  It  is  also  used  for 
optical  instruments  and  spectacle-glasses.  Even  in  ancient 
times  it  was  made  into  cups  and  vases.  Nero  is  said  to- 
have  dashed  to  pieces  two  cups  of  this  kind  on  hearing  of 
the  revolt  that  caused  his  ruin,  one  of  which  cost  him  a  sum 
equal  to  $3000. 


SILICA.  255 

Amethyst.  Purple  or  bluish- violet,  and  often  of  great 
beauty.  It  was  called  amethyst  on  account  of  its  supposed 
preservative  powers  against  intoxication.  When  finely  and 
uniformly  colored,  highly  esteemed  as  a  gem.  G.  =  2*65— 
2-66. 

Rose  Quartz.  Pink  or  rose-colored.  Seldom  occurs  in 
crystals;  generally  in  masses  much  fractured,  and  imper- 
fectly transparent.  The  color  fades  on  exposure  to  the 
light,  and  on  this  account  it  is  little  used  as  an  ornamental 
stone,  yet  is  sometimes  cut  into  cups  and  vases.  G.  =  2*65. 

False  Topaz.  Light  yellow  pellucid  crystals.  Often  cut 
and  set  for  topaz.  Absence  of  cleavage  distinguishes  it 
from  true  topaz.  The  name  citrine,  often  applied  to  this 
variety,  alludes  to  its  yellow  color. 

Smoky  Quartz.  Crystals  of  a  smoky  tint;  the  color  is 
sometimes  so  dark  as  Jo  be  nearly  black  and  opaque  except 
in  splinters.  It  is  the  cairngorm  stone.  G.  =  2-65-2*66. 

Milky  Quartz.  Milk-white,  nearly  opaque,  massive,  and 
of  common  occurrence.  Has  often  a  greasy  lustre,  and  is 
then  called  greasy  quartz.  G.  =  2" 64-2  66. 

Prase.  Leek-green,  massive;  resembling  some  shades  of 
beryl  in  tint,  but  easily  distinguished  by  the  absence  of 
cleavage  and  its  infusibility. 

Aveuturine  Quartz.  Common  quartz  spangled  through- 
out with  scales  of  golden-yellow  mica.  Usually  translucent, 
and  gray,  brown,  or  reddish  brown  in  color. 

Ferruginous  Quartz.  Opaque,  and  either  of  yellow, 
brownish-yellow,  or  red  color,  from  the  presence  of  iron 
oxide. 

II.   CHALCEDONIC   VARIETIES. 

Chalcedony.  Translucent,  massive,  with  a  glistening 
and  somewhat  waxy  lustre;  usually  of  a  pale  grayish,  blu- 
ish, whitish,  or  light  brownish  shade.  Often  occurs  lining 
or  filling  cavities  in  amygdaloidal  and  other  rocks.  The 
cavities  are  little  caverns  into  which  siliceous  waters  have, 
at  some  period,  filtrated  and  deposited  their  silica.  The 
stalactites  of  chalcedony  were  pendants  from  the  roof  of 
the  cavity.  Some  of  these  chalcedony  grottos  are  several 
feet  in  diameter.  Large  geodes  of  this  kind  occur  in  the 
Keokuk  limestone  in  Illinois  and  Iowa. 

Chrysoprase.  Apple-green  chalcedony ;  colored  by 
nickel. 


256  DESCRIPTIONS   OF   MINEKALS. 

Carnelian.  Bright  red  chalcedony,  of  a  clear,  rich  tint. 
Cut  and  polished  and  much  used  in  the  more  common 
jewelry,  and  for  seals  and  beads. 

Sard.  A  deep  brownish-red  chalcedony,  of  a  blood-red 
color  by  transmitted  light. 

Agate.  A  variegated  chalcedony.  The  colors  are  dis- 
tributed in  clouds,  spots,  or  concentric  bands.  These  bands 
take  straight,  circular,  or  zigzag  forms;  and  when  the  'last, 
it  is  called  fortification  agate,  so  named  from  the  resem- 
blance to  the  angular  outlines  of  a  fortification.  These 
bands  are  the  edges  of  layers  of  chalcedony,  and  these  layers 
are  the  successive  deposits  during  the  process  of  its  f orma- 
mation.  Mocha  stone  or  Moss  agate  is  a  brownish  agate, 
consisting  of  chalcedony  with  dendritic  or  moss-like  delin- 
eations, of  an  opaque  yellowish -brown  color.  All  the 
varieties  of  agate  are  beautiful  stones  when  polished,  but 
are  not  much  used  in  fine  jewelry.  The  colors  may  be 
darkened  by  boiling  the  stone  in  oil,  and  then  dropping  it 
into  sulphuric  acid;  a  little  oil  is  absorbed  by  some  of  the 
layers,  which  becomes  blackened  or  charred  by  the  acid. 
Agates  are  sometimes  artificially  colored  blue  and  of  other 
shades. 

Onyx.  A  kind  of  agate  having  the  colors  arranged  in 
flat  horizontal  layers ;  the  colors  are  usually  light  clear 
brown  and  an  opaque  white.  When  the  stone  consists  of 
sard  and  white  chalcedony  in  alternate  layers,  it  is  called 
sardonyx.  Onyx  is  the  material  used  for  cameos,  and  is 
well  fitted  for  this  kind  of  miniature  sculpture.  The  figure 
is  carved  out  of  one  layer  and  stands  in  relief  on  another. 
A  noted  ancient  cameo  is  the  Mantuan  vase  at  Brunswick. 
It  was  cut  from  a  single  stone,  and  has  the  form  of  a  cream- 
pot,  about  7  inches  high  and  2£  broad.  On  its  outside, 
which  is  of  a  brown  color,  there  are  white  and  yellow  groups 
of  raised  figures,  representing  Ceres  and  Triptolemus  in 
search  of  Proserpine. 

Oat's  Eye.  Greenish-gray  translucent  chalcedony,  hav- 
ing a  peculiar  opalescence,  or  glaring  internal  reflections, 
like  the  eye  of  a  cat,  when  cut  with  a  spheroidal  surface. 
The  effect  is  owing  to  filaments  of  asbestus.  It  comes  from 
Ceylon  and  Malabar,  ready  cut  and  polished,  and  is  a  gem 
of  considerable  value.  Other  hard  minerals  having  similar 
opalescence  are  included  under  the  name. 

Flinty  Hornstone,  Chert.     Massive  compact  silica,  of  dark 


SILICA.  257 

shades  of  smoky  gray,  brown,  or  even  black,  feebly  trans- 
lucent, breaking  with  sharp  cutting  edges  and  a  conchoidal 
surface.  Flint  occurs  in  nodules  in  chalk;  not  unfrequently 
the  nodules  are  in  part  chalcedonic.  Hornstone  differs  from 
flint  in  being  more  brittle,  but  is  essentially  the  same 
thing;  it  is  often  found  in  common  limestone.  Chert  is  an 
impure  hornstone.  Limestones  containing  hornstone  or 
chert  are  often  called  chert y  limestone. 

Plasma.  A  faintly  translucent  variety  of  chalcedony  ap- 
proaching jasper,  of  a  green  color,  sprinkled  with  yellow 
and  whitish  dots. 

HI.    JASPEBY  VARIETIES. 

Jasper.  A  dull  opaque  red,  yellow,  or  brownish  siliceous 
rock.  It  also  occurs  of  green  and  other  shades.  Riband 
jasper  is  a  jasper  consisting  of  broad  stripes  of  green,  yel- 
low, gray,  red,  or  brown.  Egyptian  jasper  consists  of  these 
colors  in  irregular  concentric  zones,  and  occurs  in  nodules, 
which  are  often  cut  across  and  polished.  Ruin  jasper  is  a 
variety  with  delineations  like  ruins,  of  some  brownish  or 
yellowish  shade  on  a  darker  ground.  Porcelain,  jasper  is 
nothing  but  a  baked  clay,  and  differs  from  jasper  in  being 
fusible  before  the  blowpipe.  Eed  felsyte  resembles  red 
jasper;  but  this  is  also  fusible,  and  consists  largely  of 
feldspar. 

Jasper  admits  of  a  high  polish,  and  is  a  handsome  stone 
for  inlaid  work,  but  is  not  much  used  as  a  gem. 

Bloodstone  or  Heliotrope.  Deep  green,  slightly  trans- 
lucent, containing  spots  of  red,  which  have  some  resem- 
blance to  drops  of  blood.  Contains  a  few  per  cent,  of  clay 
and  iron  oxide  mechanically  combined  with  the  silica. 
The  red  spots  are  colored  with  iron.  There  is  a  bust  of 
Christ  in  the  royal  collection  at  Paris,  cut  in  this  stone,  in 
which  the  red  spots  are  so  managed  as  to  represent  drops 
of  blood. 

Lydian  Stone,  Touchstone,  Basanite.  Velvet-black  and 
opaque,  and  used,  on  account  of  its  hardness  and  black 
color,  for  trying  the  purity  of  the  precious  metals ;  this  is 
done  by  comparing  the  color  of  the  mark  left  on  it  with 
that  of  an  alloy  of  known  character.  The  effect  of  acids 
upon  the  mark  is  also  noted. 

Besides  the  above  there  are  other  varieties  arising  from 
structure. 
17 


258  DESCRIPTIONS   OF  MINERALS. 

Tabular  Quartz.  Consists  of  thin  plates,  either  parallel 
or  crossing  one  another  and  leaving  large  open-cells. 

Granular  Quartz.  A  rock  consisting  of  quartz  grains 
compactly  cemented.  The  colors  are  white,  gray,  flesh-red, 
yellowish,  or  reddish  brown.  It  is  a  hard  siliceous  sand- 
stone. Ordinary  sandstone  often  consists  of  nearly  pure 
quartz. 

Pseudomorphous  Quartz.  Quartz  under  the  forms  of 
calcite,  barite,  fluorite,  or  other  mineral.  Shells,  corals, 
etc.,  are  sometimes  found  converted  into  quartz  by  the 
ordinary  process  of  petrifaction. 

Silicified  Wood.  Petrified  wood  often  consists  of  quartz, 
quartz  having  taken  the  place  of  the  original  wood.  In 
some  specimens  the  wood  is  converted  into  chalcedony  and 
agate  of  various  colors,  having  great  beauty  wrhen  polished. 

Quartz  with  penetrating  crystallizations.  The  kinds  are 
as  numerous  as  the  kinds  of  penetrating  minerals.  Eutile, 
asbestus,  actinolite,  and  tourmaline  sometimes  occur  in 
capillary  or  acicular  forms,  and  give  a  specimen  much  in- 
terest. The  delicate  needles  of  rutile,  m  such  cases,  must 
have  existed  in  the  rock  cavity  attached  to  its  sides  by  one 
or  both  ends,  and  the  quartz  afterward  became  deposited 
about  them;  cut  specimens  sometimes  used  in  jewelry  are 
called  in  French  Fieches  d'amour. 

Obs.  Quartz  is  a  constituent  of  granite,  gneiss,  mica 
schist,  and  many  other  common  rocks,  and  the  chief  or 
only  constituent  of  many  sandstones,  and  of  the  sands  of 
most  sea-shores  Fine  quartz  crystals  occur  in  Herkimer 
Co.,  New  York,  at  Middlefield,  Little  Falls,  Salisbury,  and 
Newport,  in  the  soil  and  in  cavities  in  a  sandstone.  The 
beds  of  iron  ore  at  Fowler  and  Hermon,  St.  Lawrence  Co., 
afford  dodecahedral  crystals.  Diamond  Island,  Lake 
George,  Pelham,  and  Chesterfield,  Mass. ;  Paris  and  Perry, 
Me.;  Meadow  Mt.,  Md.;  and  Hot  Springs,  Arkansas,  are 
other  localities.  Rose  quartz  is  found  at  Albany,  Paris, 
Stow,  Me. ;  Acworth,  N.  H. ;  and  Southbury,  Ct.  Smoky 
quartz  at  Goshen,  Mass. ;  Paris,  Me. ;  in  Burke  and  Alex- 
ander Cos.,  N.  Carolina;  at  Pike's  Peak,  Col.  (whence  it 
is  largely  exported);  and  elsewhere.  Amethyst  at  Bristol, 
E.  I.;  Delaware  and  Chester  Cos.,  Pa.;  Keweenaw  Point, 
Lake  Superior;  Clayton,  Kabun  Co.,  Ga.;  in  Arizona; 
Nevada.  Chalcedony  and  agates  in  Nova  Scotia,  poor  near 
Northampton,  and  along  the  trap  of  the  Connecticut 


SILICA.  259 

Valley — finer  near  Lake  Superior,  upon  some  of  the 
Western  rivers,  and  in  Oregon.  Chrytoprase  occurs  at 
Belmont's  lead-mine,  St.  Lawrence  Co.,  N.  Y.,  and  a  green 
quartz  (often  called  chrysoprase)  at  New  Fane,  Vt.,  along 
with  fine  drusy  quartz.  Heliotrope  occupies  veins  in  slate 
at  Bloomingrove,  Orange  County,  N.  Y.  Sihcified  wood, 
much  of  it  agatized,  abundant  near  Holbrook,  Arizona 
(whence  it  is  now  procured  for  polishing),  California,  Colo- 
orado,  Valley  of  the  Yellowstone,  etc. 

Switzerland,  Dauphiny,  Piedmont,  the  Carrara  quarries, 
and  numerous  other  foreign  localities  furnish  fine  crystals. 

The  silica  of  the  feldspars,  owing  to  the  alkali  present 
with  it — either  potash,  soda,  or  lime — is  easily  dissolved  by 
hot  waters  (those  of  geysers  and  hot  springs),  and  a  solution 
of  alkaline  silicate  is  thus  made,  much  like  the  soda-silicate 
of  the  shops  called  soluble  silica  or  ivater-glasa.  From  such 
solutions  quartz  has  been  deposited  extensively  in  the  rocks 
of  the  globe,  in  fissures  making  quartz  veins;  in  cavities 
small  and  large,  making  geodes  of  chalcedony,  agate,  or  of 
quartz  crystals,  or  filling  the  cavities  solid;  or  silicifying 
wood.  Some  porous  kinds  of  igneous  rocks  or  lavas 
(trachytes  and  allied  kinds),  and  especially  the  beds  made 
of  volcanic  debris  or  tufas,  undergo  alteration  easily  through 
the  action  of  percolating  waters,  and  little  heat  is  required 
for  it;  and  where  volcanic  debris  (ashes,  scoria)  have 
covered  forests,  the  trees  of  the  forests  have  been  silicified 
over  large  areas,  as  in  California,  Arizona,  and  Nevada. 
The  feldspar  in  the  change  is  converted  into  kaolin,  and  in 
the  process  a  fourth  to  a  third  of  the  silica  is  set  free;  be- 
sides, p}Toxene  or  hornblende,  if  present,  loses  also  as  large 
a  part  of  the  silica;  consequently  the  supply  of  discharged 
silica  is  very  large.  The  liberated  silica,  besides  making 
quartz^  often  makes  opal,  another  form  of  silica;  and  this 
is  the  chief  source  of  opal.  It  often  produces,  also,  by 
combination  with  the  alumina  and  other  bases  at  hand, 
various  silicates  in  the  cavities  or  fissures  of  the  rocks,  like 
the  zeolites — minerals  usually  found  in  the  cavities  of  igne- 
ous rocks. 

Opal. 

.  Compact  and  amorphous,  texture  colloid;  also  in  reni- 
form  and  stalactitic  shapes;  also  earthy.  Colors  white, 
yellow,  red,  brown,  green,  blue,  and  gray.  The  finest 


260  DESCRIPTIONS   OF   MINERALS. 

varieties  exhibit  from  within,  when  turned  in  the  hand, 
a  rich  play  of  colors  of  delicate  shades.  Lustre  waxy  to 
subvitreous.  H.  =  5-5-6-5.  G.  =  l'9-2'3. 

Composition.  Consists  of  silica,  like  quartz;  but  of  silica 
in  a  different  molecular  state,  the  hardness  and  specific 
gravity  being  less;  and  it  being  soluble  in  a  strong  alkaline 
solution,  especially  if  heated.  Usually  contains  a  few  per 
cent,  of  water — amounting  in  some  kinds  to  12  per  cent. ; 
but  the  water  is  not  generally  regarded  as  an  essential  con- 
stituent. Differs  from  quartz  also  in  its  lustre,  which  is 
more  waxy  than  chalcedony;  also  in  the  total  absence  of  a 
crystalline  texture. 

VARIETIES. 

Precious  Opal.  External  color  usually  milky,  but  hav- 
ing within  a  rich  play  of  delicate  tints;  a  gem  of  rare 
beauty.  A  large  mass  in  the  imperial  cabinet  of  Vienna 
weighs  seventeen  ounces,  and  is  nearly  as  large  as  a  man's 
fist,  but  contains  numerous  fissures  and  is  not  entirely  dis- 
engaged from  the  matrix.  This  stone  was  well  known  to 
the  ancients  and  highly  valued  by  them.  They  called  it 
Paideros,  or  Child  Beautiful  as  Love.  The  noble  opal  is 
found  near  Cashau  in  Hungary,  and  in  Honduras,  South 
America;  also  on  the  Faroe  Islands;  at  Esperanza,  in 
Mexico. 

Fire  Opal,  Girasol.  An  opal  with  yellow  and  bright 
hyacinth  or  fire-red  reflections.  It  comes  from  Mexico  and 
the  Faroe  Islands;  Washington  Co.,  Ga.  A  beautiful  blue 
opal  occurs  in  Queensland,  Australia. 

Common  Opal,  Semiopal.  Has  the  hardness  of  opal,  its 
waxy  or  resinous  lustre,  but  no  colored  reflections  from 
within,  though  sometimes  a  milky  opalescence.  The 
colors  are  white,  gray,  red,  yellow,  bluish,  greenish  to 
dark  grayish-green.  Translucent  to  nearly  opaque.  *  Occurs 
with  some  of  the  silicified  wood  of  Arizona,  etc.,  but  much 
of  it  retains  some  of  the  structure  of  the  wood,  and  is  wood- 
opal. 

HydropJiane.  Opaque  white  or  yellowish  when  dry,  but 
translucent  and  opalescent  after  immersion  in  water. 

CacJwlong.  Opaque  white,  or  bluish  white ;  usually 
associated  with  chalcedony.  Part  so  called  is  chalcedony ; 
other  specimens  contain  water,  and  are  allied  to  hydrophane. 
Contains  also  a  little  alumina  and  adheres  to  the  tongue. 


SILICA.  261 

Hyalite,  Midler's  Glass.  Glassy  transparent ;  in  small 
concretions,  occasionally  stalactitic.  Eesembles  somewhat 
transparent  gum-arabic.  An  analysis  obtained  Silica  92-00, 
water  6 '33. 

Menilite.  Brown,  opaque;,  compact  reniform;  occasion- 
ally slaty.  Composition,  Silica  85 -5,  water  ll'O  (Klaproth). 
In  slate  at  Menil  Montant,  near  Paris. 

Wood  Opal.  Gray,  brown,  or  black,  having  the  structure 
of  wood,  being  wood  petrified  with  hydrated  silica  (or  opal), 
instead  of  quartz. 

Opal  Jasper.  Resembles  jasper  in  color,  due  to  a  little 
iron;  but  is  resinous  in  lustre  and  not  so  hard. 

Siliceous  Sinter,  Geyterite.  A  loose,  porous  siliceous 
rock,  grayish  to  white  in  color;  deposited  around  geysers, 
as  those  of  Iceland  and  the  Yellowstone  Park,  in  cellular 
or  compact  masses,  sometimes  in  stalactitic  or  cauliflower- 
like  shapes.  Viamlite  is  an  unusually  hydrous  variety,  a 
leathery  incrustation  which  crumbles  on  drying:  from 
the  Yellowstone  Park.  Pearl  sinter,  or  Fiorite,  occurs  in 
volcanic  tufa  in  smooth  and  shining  globular,  botryoidal 
masses,  having  a  pearly  lustre. 

Float  Stone.  A  variety  of  opal  having  a  porous  and  fibrous 
texture,  and  hence  so  light  that  it  will  float  on  water.  It 
occurs  in  concretionary  or  tuberose  masses,  which  often 
have  a  nucleus  of  quartz. 

Tripolite  (Diatomite,  Infusorial  Earth).  A  white  or 
grayish- white  earth,  massive,  laminated,  or  slaty,  made 
mainly  of  siliceous  secretions  of  microscopic  plants  called 
Diatoms,  with  more  or  less  of  the  spicules  of  sponges. 
Forms  beds  of  considerable  extent,  and  often  occurs  beneath 
peat  (because  diatoms  lived  in  the  waters  of  the  shallow 
pond  before  it  became  a  drying  marsh) ;  as  in  Maine,  New 
Hampshire,  Nevada,  California.  It  is  sold  as  a  polishing 
powder  under  the  name  of  electro  silicon.  Dynamite  was 
formerly  made  by  mixing  nitroglycerine  (liquid)  with  it, 
but  woodpulp  is  now  used  instead.  It  is  used  for  making 
solutions  of  soluble  silica  (soda  silicate),  for  purposes  of  a 
cement.  Owing  to  its  poor  conduction  of  heat,  it  has  been 
applied  as  a  protection  to  steam  boilers  and  pipes. 

Tabaslieer  is  a  siliceous  aggregation  found  in  the  joints 
of  the  bamboo  in  India,  and  not  properly  a  mineral.  Con- 
tains several  per  cent,  of  water,  and  has  nearly  the  appear- 
ance of  hyalite. 


262  DESCRIPTIONS   OF   MINERALS. 

Diff.  Infusibility  before  the  blowpipe  is  the  best  charac- 
ter for  distinguishing  opal  from  pitchstone,  pearlstone,  and 
other  species  it  resembles.  The  absence  of  anything  like 
cleavage  or  crystalline  structure  is  another  characteristic. 
Its  inferior  hardness,  specific  gravity,  and  resinous  dr  greasy 
lustre,  separate  it  from  quartz. 

Tridymite.  Pure  silica,  like  quartz  and  opal,  with  very  nearly  the 
hardness  and  specific  gravity  of  opal,  but  occurring  in  tabular  hexag- 
onal prisms,  1  A  1  —  127°  35'  over  a  pyr- 
amidal edge  and  124°  3'  over  /.  If  not 
crystallized  opal,  it  is  a  third  state  of 
SiO2.  In  trachytic  and  some  other  vol- 
canic rocks  in  Germany;  island  Vul- 
cano;  Mexico;  Yellowstone  Park;  Col- 
orado, etc.  Asmanite  is  the  same  from  meteorites. 

Jenzschite.  Silica,  SiO2,  in,  it  is  supposed,  a  fourth  state,  it  resem- 
bling opal  in  aspect  and  in  solubility  in  alkaline  solutions,  but  having 
the  specific  gravity  of  quartz,  or  26.  Hilttenberg,  Carinthia ;  near 
Weissig  ;  Regensberg ;  Brazil. 

Melanophlogite.      Colorless  cubes  (pseudomorphs  ?)  consisting  of 
silica,  with  a  little  sulphur  trioxide  and  water.     On  Sulphur,  Sicily. 
Proidonite.      Silicon  fluoride.      Observed    as  an    exhalation    at 
Vesuvius  in  1872.  Hieratile;  2KF+  SiF4,  Yulcano. 

2.  SILICATES. 

The  Silicates  are  here  divided  into  the  Anhydrous  and  the 
Hydrous. 

In  part  of  the  Anhydrous  Silicates,  the  combining  value 
or  quantivalence  (see  page  88)  of  the  silicon  is  to  that  of 
the  basic  elements  as  2  to  1;  in  another  part,  as  1  to  1; 
and  in  a  third  division,  as  less-than-1  to  1.  On  this  ground 
the  mineral  silicates  are  here  arranged  in  three  groups, 
named  respectively  :  I.  BISILICATES  ;  II.  UNISILICATES  ; 
and  III.  SUBSILICATES. 

In  the  Bisilicates,  one  molecule  of  silicon  is  combined 
with  one  molecule  of  an  element  in  the  protoxide  state,  as 
Mg,  Ca,  Fe,  etc.,  or  one  third  of  a  molecule  of  an  element 
in  the  sesquioxide  state,  as  Al,  Fe,  Mn,  etc.;  or,  what  is 
the  same  thing,  3  molecules  of  silicon,  with  3  of  an  element 
in  the  protoxide  state,  or  1  of  an  element  in  the  sesquioxide 
state.  The  general  formulas  of  such  compounds  is  hence 
R03Si,  or  R09Si3,  or,  if  elements  in  both  the  protoxide  and 
sesquioxide  state  are  present,  (R3R)09Si3,  as  explained  on 
page  91. 


BISILICATES.  263  - 

In  the  Unisilicates,  one  molecule  of  silicon  is  combined 
with  two  of  an  element  in  the  protoxide  state,  that  is,  for 
example,  Mg2,  Ca2,  Fe2;  or  with  two  thirds  of  a  molecule  in 
the  sesquioxide  state,  that  is,  two  thirds  of  Al,  Fe,  Mn. 
The  formula  of  these  silicates  is  hence  R.,04Si,  or  Rf  04Si, 
or,  in  order  to  remove  the  fraction  in  the  last,  R2012Sis; 
which  becomes,  when  elements  in  the  protoxide  and  ses- 
quioxide state  are  both  present,  (R3,  R)2012Si3. 

Among  the  species  referred  to  the  Unisilicates  there  are 
some  that  vary  from  the  unisilicate  ratio.  This  occurs 
especially  in  species  in  which  an  alkali  is  present,  as  in  the 
Feldspars,  Micas,  and  Scapolites. 

The  Subsilicates  vary  in  the  proportion  of  the  silicon  to 
the  basic  elements,  and  graduate  into  the  Unisilicates. 

The  same  three  grand  divisions  exist  more  or  less  satis- 
factorily-among  the  Hydrous  Silicates. 

Some  hydrous  silicates  give  evidence,  by  holding  to  the 
water  when  highly  heated,  that  the  water  is  basic  (that  is, 
its  hydrogen  replaces  the  metal  of  other  oxides  among  the 
bases);  and  these,  therefore,  are  here  arranged  with  the 
anhydrous  species.  Some  examples  are  epidote,  zoisite,  and 
euclase. 

Specimens  of  the  anhydrous  silicates  often  contain  2  or 
3  p.  c.  of  water  as  a  consequence  of  incipient  alteration. 


A.   ANHYDROUS  SILICATES. 


I.  BISILICATES. 

The  bisilicates,  when  the  base  is  in  the  protoxide  state 
and  have  hence  the  general  formula  R03Si,  are  resolved  in 
analyses  into  protoxides  and  silica  in  the  ratio  of  IEO  to 
!Si02,  in  which,  as  the  term  Msilicate  implies,  the  oxygen 
of  the  silica  is  twice  that  of  the  protoxides.  If  the  base  is 
in  both  the  protoxide  and  sesquioxide  states,  giving  the  for- 
mula (R3,  R)  09Si3,  the  mineral  is  resolved  in  analyses  into 
protoxides,  sesquioxides,  and  silica.  If  the  ratio  of  the  pro- 
toxides to  sesquioxides  is  1  :  1,  the  formula  will  become 
^R3£R09Si3  which,  doubled,  to  clear  it  of  the  fractions, 
becomes  R3R018Sifi;  and  analyses  give  then  for  the  oxides 
and  silica  3RO,  1R08,  GSiOa. 


264  DESCRIPTIONS   OF  MINERALS. 

Among  the  following  Bisilicates  the  species  from  ensta- 
tite  to  spodumene  and  amphibole  make  a  natural  group 
called  the  hornblende,  or  hornblende  and  pyroxene  group. 
They  are  closely  related  in  composition  and  also  in  crystal- 
lization. The  cleavage  prism  is  rhombic,  and  has  either  an 
angle  of  about  124^°  or  of  about  87°;  and  the  former  of 
these  two  rhombic  prisms  has  just  twice  the  breadth  of  the 
other;  that  is,  if  the  lateral  axis  from  the  front  to  the  back 
edge  in  each  be  taken  as  unity,  the  other  lateral  axis  is  twice 
as  long  in  the  prism  of  124^-°  as  it  is  in  that  of  87°  5'. 
The  forms  are  either  orthorhombic,  monoclinic,  or  tri clinic; 
and  yet  close  relations  in  angles,  as  just  stated,  exist  be- 
tween them.  Enstatite  is  a  magnesium  or  magnesium  and 
iron  species;  wollastonite,  a  calcium  species;  rhodonite,  a 
manganese  species;  pyroxene  and  hornblende  contain  cal- 
cium with  magnesium  or  iron ;  spodumene  contains  lithium 
and  aluminium,  aluminium  replacing  elements  that  in 
other  species  are  in  the  protoxide  state. 

Enstatite.— Bronzite. 

Orthorhombic;  I /\  I  =  88°  16'.  Prismatic  cleavage 
easy.  Usually  possesses  a  fibrous  appearance  on  the  cleav- 
age surface.  Also  massive  and  lamellar. 

Color,  grayish,  yellowish  or  greenish  white,  or  brown. 
Lustre  pearly ;  often  metalloidal  in  the  bronzite  variety. 
H.  5-5.  G.  3-1-3-3. 

Composition.  Mg03Si  =  Silica  60,  magnesia  40.  B.B. 
infusible,  and  insoluble.  Bronzite  has  a  portion  of  the 
magnesium  replaced  by  iron. 

Diff.  Kesembles  amphibole  and  pyroxene,  but  is  infusi- 
ble, and  orthorhombic  in  crystallization. 

Obs.  Occurs  in  the  Vosges ;  Moravia ;  Bavaria;  Baste, 
in  the  Hartz;  Brewster's,  N.  Y.;  Leiperville,  Texas,  Mar- 
pie,  Kadnor's,  Pa.;  Bare  Hills,  Md. 

Hypersthene.  Near  bronzite  in  form  and  composition,  but  contains 
a  larger  percentage  of  iron  and  B.B.  fuses;  on  charcoal,  becomes 
magnetic.  St.  Paul's  Island,  in  Labrador;  Isle  of  Skye;  Greenland; 
Norway,  etc.  Szaboite  is  hypersthene;  Amblystegite  contains  still 
more  iron;  Diaclasite  is  near  bronzite. 


BISILICATES.  265 


Wollastonite. — Tabular  Spar. 

Monoclinic;  I/\I=8T  28',  C  =69°  48'.  Earely  in 
oblique  flattened  prisms;  usually  massive.  Cleaves  easily 
in  one  direction,  affording  a  lined  or  indistinctly  columnar 
surface.  Usually  white,  but  sometimes  tinged  with  yellow, 
red,  or  brown.  Translucent,  or  rarely  subtransparent. 
Lustre  vitreous,  pearly.  Brittle.  H.  =  4  '5-5.  G-.  —  2*85- 
2-91. 

Composition.  Ca03Si  =  Silica  52,  lime  48  =  100.  B.B. 
fuses  with  difficulty  to  a  subtransparent,  colorless  glass;  in 
powder  decomposed  by  hydrochloric  acid,  and  the  solution 
gelatinizes  on  evaporation;  often  effervesces  when  treated 
with  acid  on  account  of  the  presence  of  calcite. 

Diff.  Differs  from  asbestus  and  tremolite  in  its  more  vit- 
reous appearance  and  fracture,  and  by  its  gelatinizing  in 
acid;  from  the  zeolites  by  the  absence  of  water,  which  all 
zeolites  give  in  a  closed  tube;  from  feldspar  in  the  fibrous 
appearance  of  a  cleavage  surface  and  the  action  of  acids. 

Obs.  Usually  found  in  granite  or  granular  limestone; 
occasionally  in  basalt  or  lava.  Occurs  in  Ireland  at  Dun- 
more  Head;  at  Vesuvius  and  Capo  di  Bove;  in  the  Hartz; 
Hungary;  Sweden;  Finland;  Norway. 

At  Willsboro',  Lewis,  Diana,  and  Koger's  Rock,  N.  Y., 
of  a  white  color,  along  with  garnet;  at  Boonville,  in  bowl- 
ders with  garnet  and  pyroxene;  Grenville,  Canada;  in 
Bucks  Co.,  Pa.;  at  Keweenaw  Point,  L.  Superior.  Edel* 
forsite  is  impure  wollastonite. 

Pyroxene. — Augite. 

Monoclinic.  /A  7  =  87°. 5',  C-  73°  59'  =  0  A  i-i- 
Cleavage  perfect  parallel  with  the  sides  of  this  prism,  and 
often  distinct  parallel  with  the 
diagonals.  Usually  in  thick 
and  stout  prisms,  of  4,  6,  or  8 
sides,,  terminating  in  two  faces 


meeting  at  an  edge.     /  A  i-i  — 
133°   33',   /A*-i  = 


136°   27'; 

-1  A-l  =  131°  24'.    Often  twin- 
ned parallel  to  i-i  ;  also  often  lamellar  parallel  to  0,  owing 
to  the  interposition  of  twinning  lamellae.     Massive  varieties 


266  DESCRIPTIONS   OF   MINERALS. 

of  a  coarse  lamellar  structure;  also  fibrous,  fibres  often  very 
fine  and  often  long  capillary.  Also  granular;  usually  coarse 
granular  and  friable;  grains  usually  angular,  sometimes 
round.  Also  compact  massive. 

Colors  green  of  various  shades,,  verging  to  white  on  one 
side  and  brown  and  black  on  the  other,  passing  through 
blue  shades,  but  not  yelloio.  Lustre  vitreous,  inclining  to 
resinous  or  pearly;  the  latter  in  fibrous  varieties.  Trans- 
parent to  opaque.  H.  =  5-6.  Gr.  —  3'2-3'5. 

Composition.  R03Si  (or  RO  -|-  Si02);  in  which  R  may 
be  Ca,  Mg,  Fe,  Mn,  and  sometimes  Zn,  K2,  Na2,  these 
bases  replacing  one  another  without  changing  the  crystal- 
line form,  of  .which  two  or  more  are  usually  present ;  the 
first  three  are  most  common.  Calcium  is  always  present. 
The  following  is  an  analysis  of  a  typical  variety:  Silica  55 '0, 
lime  23 *5,  magnesia  16*5,  manganese  protoxide  *5,  iron  pro- 
toxide 4-5  =  100.  Fuses  B.B.,  but  the  fusibility  varies 
with  the  composition,  and  the  ferriferous  varieties  are  most 
fusible.  Insoluble  in  acids. 

Diff.  The  crystalline  form,  and  ready  cleavage  in  two 
planes  nearly  at  right  angles  to  one  another  (87°  5'),  are 
the  best  characters  for  its  determination. 

VARIETIES. — The  varieties  may  be  divided  into  three  sec- 
tions—the light  colored,  the  dark  colored,  and  the  thin 
foliated. 

I.  Malacolite  or  white  augite,  a  calcium-magnesium  py- 
roxene, including  white  or  grayish  white  crystals  or  crystal- 
line masses.  Diopside,  of  the  same  composition,  in  green- 
ish white  or  grayish  green  crystals,  and  cleavable  masses 
cleaving  with  a  bright  smooth  surface.  Sahlite,  containing 
iron  in  addition,  and  of  a  more  dingy  green  color,  with  less 
lustre  and  a  coarser  structure  than  diopside,  but  otherwise 
similar ;  named  from  the  place  Sala,  where  it  occurs. 
•Fassaite,  containing  a  little  alumina  in  addition  to  the  ele- 
ments of  sahlite,  and  found  in  crystals  of  rich  green  shades 
and  smooth  and  lustrous  exterior;  named  from  the  foreign 
locality,  Fassa.  Coccolite,  coarsely  granular,  named  from 
the  Greek  coccos,  grain  ;  when  green,  called  green  coccolite ; 
white,  white  coccolite.  The  specific  gravity  of  these  varie- 
ties varies  from  3*25  to  3*3. 

Asbestus.  Includes  fibrous  varieties  of  both  pyroxene 
vand  hornblende;  it  is  more  particularly  noticed  beyond, 
under  the  latter  species,  as  pyroxene  is  rarely  asbestiform. 


BISILICATES.  267 

II.  A ugite.    The  black  and  greenish  black  crystals,  which 
contain  a  larger  percentage  of  iron,  or  iron  and  magnesium, 
and  which  mostly  present  the  form  in  figure  1.     Specific 
gravity  3  *3-3  *4.     This  is  the  common  pyroxene  of  eruptive 
rocks.    Hedenbergite,  an  iron-calcium  pyroxene,  a  greenish 
black  opaque  variety,  in  cleavable  masses  affording  a  green- 
ish brown  streak;  specific  gravity  3 '5.     Manganhedenberg- 
ile,  near  the  last,  contains  6  to  7  p.  c.  of  manganese  pro- 
toxide; G.  =  3*55.     Polylite,  Hudsonite,  and  Jeffersonite 
fall  here;  the  last  contains  some  zinc  oxide.     These  varieties 
fuse  more  easily  than  the  preceding,  and  the  globule  ob- 
tained is  colored  black  by  the  iron  oxide. 

III.  Diallage,  a  thin-foliated  variety,  often  occurring  im- 
bedded in  serpentine  and  some  other  rocks.     Differs  from 
bronzite  and  hypersthene  in  crystallization,  and  in  being 
more  fusible ;  the  foliation  is   often  a  result  of  incipient 
alteration,  p.  450. 

Obs.  Pyroxene  is  one  of  the  most  common  minerals.  It 
is  a  constituent  in  almost  all  basic  eruptive  rocks,  like  basalt, 
and  is  frequently  met  with  in  rocks  of  other  kinds;  a  white 
kind  is  common  in  granular  limestone,  and  also  a  green. 
In  basalt  or  lavas  the  crystals  are  generally  small  and 
black  or  greenish  black.  In  other  rocks  it  occurs  of  all 
the  shades  of  color  given,  and  the  crystals  of  all  sizes  to  a 
foot  or  more  in  length.  One  crystal  from  Orange  County, 
measured  6  inches-  in  length,  and  10  in  circumference. 
White  crystals  occur  at  Canaan,  Ct. ;  Sheffield,  Monterey, 
Mass. ;  Kingsbridge,  New  York  County,  and  the  Sing  Sing 
quarries,  Westchester  Co.,  N.  Y. ;  in  Orange  Co.  at  several 
localities;  green  crystals  at  Trumbull,  Ct.,  at  various  places 
in  Orange  Co.,  N".  Y.,  Roger's  Rock  and  other  localities  in 
Essex,  Lewis,  and  St.  Lawrence  Cos.  Dark  green  or  black 
crystals  are  met  with  near  Edenville,  N.  Y.,  Diana,  Lewis 
Co.  Large  crystals  occur  with  the  apatite  of  Renfrew, 
Canada.  Jeffersonite  occurs  at  Franklin,  in  1ST.  J.  Green 
coccolite  is  found  at  Roger's  Rock,  Long  Pond,  and  Wills- 
boro',  N.  Y. ;  black  coccolite,  in  the  forest  of  Dean,  Orange 
Co.,  N.  Y.  Diopside,  at  Raymond  and  Rumford,  Me.; 
Hustis's  farm,  Phillipstown,  and  De  Kalb,  N.'Y.;  Fort 
Defiance,  Ariz.;  Gallup,  N.  Mex. 

Pyroxene  was  thus  named  by  Hauy  from  the  Greek  pur, 
fire,  and  zenos,  stranger,  in  allusion  to  its  occurring  in 


268  DESCRIPTIONS   OF  MINERALS. 

lavas,  where  Haiiy  thought  it  did  not  belong,  or  was  a  guest. 
The  name  Augite  is  from  the  Greek  auge,  lustre. 

JEgirite.  Black  to  greenish  black  in  color.  A  pyroxene  contain- 
ing nearly  10  per  cent,  of  soda,  and  much  iron  sesquioxide.  Near 
Brevig  in  Norway  ;  Hot  Springs,  Arkansas. 

Acmite.  In  long  highly-polished  prisms,  of  a  dark  brown  or  red- 
dish brown  color,  with  a  pointed  extremity.  /A/=  86°  56',  resem- 
bling pyroxene  ;  contains  over  12  per  cent,  of  soda  ;  B.B.  fuses  easily. 
In  granite,  near  Kongsberg,  Norway ;  in  nepheline  rock  near 
Montreal. 

Babingtonite.  Resembles  some  varieties  of  pyroxene ;  crystals 
greenish  black,  splendent.  In  quartz,  Arendal,  Norway. 

Uralite.  Has  the  form  of  pyroxene  but  cleavage  of  hornblende ; 
and  has  been  produced  through  the  alteration  of  pyroxene  to  horn- 
blende. Some  Archaean  and  igneous  rocks  that  are  now  hornblendic 
were  originally  pyroxene  rocks. 

Rhodonite. — Manganese  Spar,  Fowlerite. 

Triclinic,  but  nearly  isomorphous  with  pvroxene.  Also 
massive. 

Color  reddish,  commonly  deep  flesh-red;  also  brownish, 
greenish,  or  yellowish,  when  impure;  very  often  black  on 
the  surface;  streak  uncolored.  Lustre  vitreous.  Transpa- 
rent to  opaque.  Becomes  black  on  exposure.  H.  =  5  '5— 
6-5.  G.  =  3-4-3-7. 

Composition.  Mn03Si  =  Silica  45 '9,  manganese  protox- 
ide 54 '1  =  100.  It  commonly  contains  a  little  iron  and 
lime  replacing  the  manganese.  Becomes  dark  brown  when 
heated;  with  borax  in  the  outer  flame,  gives  a  deep  violet 
color  to  the  bead  while  hot,  a  red-brown  when  cold.  A  va- 
riety containing  a  little  zinc,  from  Franklin  Furnace,  !NT.  J., 
has  been  named  Keatingine. 

Diff.  Resembles  somewhat  a  flesh-red  feldspar,  but  differs 
in  greater  specific  gravity,  in  blackening  on  exposure,  and 
in  the  glass  with  borax. 

Obs.  Occurs  in  Sweden,  the  Hartz,  Siberia,  and  else- 
where. In  the  United  States  it  is  found  at  Blue  Hill  Bay, 
Me.;  Plainfield  and  Cummington,  Mass.;  abundantly  at 
Hinsdale,  and  on  Stony  Mountain,  near  Winchester,  N.  H. ; 
in  crystals  at  Franklin  Furnace,  NT.  J.;  at  Alice  Mine, 
Butte  City,  Montana.  The  black  exterior  is  a  more  or  less 
pure  hydrated  oxide  of  manganese,  produced  by  oxidation. 
A  hydrous  rhodonite  has  been  called  Hydro-rhodonite. 

Rhodonite  may  be  used  in  making  a  violet-colored  glass, 


BISILICATES.  269 

and  also  for  a  colored  glazing  on  stoneware.     It  receives  a 
high  polish  and  is  sometimes  employed  for  inlaid  work. 

Spodumene. 

Monoclinic.  I/\I=  87°,  C  =  69°  40',  being  near  pyrox- 
ene. Cleavage  easy,  parallel  to  /  and  i-i.  Surface  of 
cleavage  pearly.  Color  grayish  or  greenish;  pale  amethys- 
tine; rarely  emerald-green.  Lustre  of  cleavage  surface 
pearly.  Translucent  to  subtranslucent.  H.  =  6  -5-7.  G. 
=  3  -15-3  -19. 

Composition.  (R3,  Al)09Si3,  in  which  R  equals  Li2,  and 
3Lia  is  to  Al  as  1  :  3;  this  corresponds  to  Li2A10]2Si4  = 
Silica  64-9,  alumina  27'6,  lithia  7'5  =  100.  B.B.  becomes 
white  and  opaque,  fuses,  swells  up,  and  imparts  to  the  flame 
the  purple-red  flame  of  lithia.  Unaffected  by  acids. 

Diff.  Resembles  feldspar  and  scapolite,  but  has  a  higher 
specific  gravity  and  a  more  pearly  lustre,  and  affords  rhom- 
bic prisms  by  easy  cleavage.  The  lithia  reaction  is  its 
most  characteristic  test. 

Obs.  Occurs  in  granite  at  Goshen,  Chesterfield,  Norwich, 
and  Sterling,  Mass. ;  at  Windham,  Me. ;  at  Brookfield  and 
Branchville,  Ct. ;  at  Stony  Point,  Alexander*  Co.,  ET.  C., 
an  emerald-green  variety  (Hiddenite)  rivalling  the  emerald 
as  a  gem;  2  m.  from  Harney,  Black  Hills,  Dak. ;  at  Uto, 
in  Sweden;  Sterzing  in  the  Tyrol;  and  at  Killiney  Bay, 
near  Dublin.  Some  crystals  from  Branchville,  Goshen,  and 
the  Black  Hills  a  yard  or  more  long.  Cymatolite  (a  mixture 
of  albite  and  muscovite),  Killinite,  muscovite,  albite,  micro- 
dine  y  eucryptite,  are  among  the  results  of  its  alteration  at 
Branchville. 

This  mineral  is  remarkable  for  the  lithia  it  contains. 

Petalite. 

Monoclinic.  In  imperfectly  cleavable  masses;  most 
prominent  cleavage  angle  141°  30'.  Color  white,  gray, 
pale  reddish,  greenish.  Lustre  vitreous  to  sub-pearly. 
Translucent.  H.  =  6-6-5.  G.  =  2-5. 

Composition.  Contains  lithia,  like  spodumene,  and 
affords  Silica  77'9,  alumina  17'7,  lithia  3'1,  soda  1-3  =  100. 
Phosphoresces  when  gently  heated.  Fuses  with  difficulty 
on  the  edges.  Reacts  for  lithia. 


270 


DESCRIPTIONS   OF   MINERALS. 


Diff.  Like  spodumene  in  the  lithia  reaction,  but  unlike 
it  in  lustre,  specific  gravity,  and  greater  fusibility. 

Ob$.  From  Uto,  Sweden;  also  from  Elba  ( Castor  or  Cas- 
forite).  An  alteration  product  of  castor  has  been  called 
Hydrocastorite. 


Amphibole. — Hornblende. 

Monoclinic;  I/\I=  124°  30,  C=  75°  2'.  Cleavage  per- 
fect parallel  with  /.  Often  in  long, 
slender,  flat  rhombic  prisms  (Fig.  2), 
breaking  easily  transversely;  also  often 
in  6-sided  prisms,  with  oblique  extremi- 
ties. Frequently  columnar,  with  a  bladed 
structure;  long  fibrous  or  asbestiform,  the 
fibres  coarse  or  fine,  often  like  flax,  and 
pearly  or  silky;  also  lamellar;  also  granu- 
lar, either  coarse  or  fine. 

Colors  white  to  black,  passing  through 
bluish  green,  grayish  green,  green,  and 
brownish  green  shades,  to  black.  Lustre  vitreous,  with 
the  cleavage  face  inclining  to  pearly;  fibrous  varieties  silky. 
Nearly  transparent  to  opaque.  H.  =  5-6.  G.  =  2 -9-3 -4. 
Composition.  RO?Si  (or  RO  -f  SiOa),  as  for  pyroxene. 
R  may  correspond  to  two  or  more  of  the  basic  elements  Mg, 
Ca,  Fe,  Mn,  JSTa2,  K2,  the  first  three  being  most  common. 
Aluminium  often  replaces  a  portion  of  the  silicon.  B.  B.  as 
in  pyroxene;  fuses,  but  the  fusibility  varies  indefinitely, 
being  easiest  in  the  black  varieties. 

Diff.  Distinguished  from  pyroxene  by  the  very  ready 
cleavages  parallel  to  a  prism  of  124^°,  and  the  prevalence 
of  6-sided  prisms  or  sharp  rhombic  instead  of  87°  5'. 

This  species,  like  pyroxene,  has  numerous  varieties,  dif- 
fering much  in  external  appearance,  and  arising  from  the 
same  causes — isomorphism,  and  crystallization.  The  fol- 
lowing are  the  most  important : 


I.   LIGHT-COLORED  VARIETIES. 


Tremolite,  Grammatite.  White  and  grayish,  in  bladed 
crystallizations  and  long  crystals  penetrating  the  gangne 
or  aggregated  into  coarse  columnar  forms.  Sometimes 
nearly  transparent.  G-.  =  2*9.  Formula  (Ca,  Mg)08Si  = 


BISILICATES.  271 

Silica  57-70,  magnesia  28 -85,  lime  13-45  =  100.  Named 
from  Tremola,  in  Switzerland,  where  it  is  not  found. 

Actinolite.  Light  green  fibrous,  columnar  and  prismatic, 
and  massive;  a  magnesium- calcium-iron  amphibole.  Glassy 
actinolite  includes  the  bright  glassy,  green  crystals,  usually 
long  and  slender,  and  penetrating  the  gangue  like  tremo- 
lite;  radiated,  olive-green  masses,  consisting  of  aggrega- 
tions of  coarse  acicular  fibres,  radiating  or  divergent;  asbes- 
tiforni,  resembles  the  radiated,  but  the  fibres  more  delicate; 
G.  =  3-0-3*1.  Named  actinolite  from  the  Greek,  aktin,  a 
ray  of  the  sun,  referring  to  the  frequent  radiated  structure. 

Composition  of  glassy  actinolite:  Silica  59*75,  magnesia 
21*1,  lime  14*25,  iron  protoxide  3*9,  manganese  protoxide 
0-3,  hydrofluoric  acid  0*8  (Bonsdorf). 

Asbestus.  In  slender  fibres  easily  separable,  and  some- 
times like  flax.  Either  green  or  white.  Amianthus  in- 
cludes fine  silky  varieties.  (Much  so  called  is  serpentine ; 
serpentine  is  hydrous,  and  is  thereby  easily  distinguished.) 
Liyniform  asbestus  is  compact  and  hard,  brownish  and 
yellowish  in  color,  looking  like  petrified  wood.  Mountain 
leather  occurs  in  thin,  tough  sheets,  feeling  a  little  like  kid 
leather;  consists  of  interlaced  fibres  of  asbestus,  and  forms 
thin  seams  between  layers  or  in  fissures  of  rocks.  Mountain 
cork  is  similar,  but  is  in  thicker  masses;  it  has  the  elasticity 
of  cork,  and  is  usually  white  or  grayish  white.  Breislakite 
is  a  wool-like  variety  from  Vesuvius. 

The  preceding  light-colored  varieties  contain  little  or  no 
alumina  or  iron. 

Nephrite.  A  tough  compact  variety,  related  to  tremolite. 
Color  light  green  or  blue.  Breaks  with  a  splintery  fracture 
and  glistening  lustre.  H.  =  6-6-5.  G.  =  3.  A  magne- 
sium-calcium amphibole.  Nephrite  is  made  into  images, 
and  was  formerly  worn  as  a  charm.  It  was  supposed  to  be 
a  cure  for  diseases  of  the  kidney,  whence  the  name,  from 
the  Greek,  nephros,  kidney.  In  New  Zealand,  China,  and 
Western  America  it  is  carved  by  the  inhabitants,  or  pol- 
lished  down  into  various  fanciful  shapes.  It  is  called  jade; 
but  the  aluminium-sodium  silicate,  called  jadeite,  is  the 
stone  most  highly  prized  of  all  that  pass  under  the  name 
of  jade.  Part. of  the  "  jade"  of  China  is  prehnite. 


272  DESCRIPTIONS   OF   MINERALS. 


H.   DARK-COLORED  VARIETIES 


Cummingtonite.  A  magnesium-iron  amphibole ;  color 
gray  or  brown;  usually  fibrous.  Named  from  the  locality 
where  found,  Cummington,  Mass. 

Parqasite.  Dark  green  crystals,  short  and  stout  (resem- 
bling Fig.  4),  with  bright  lustre,  of  which  Pargasin  Finland 
is  a  noted  locality.  G-.  —  3*11.  Composition:  Silica  45-5, 
alumina  14-9,  iron  protoxide  8*8,  manganese  protoxide  1*5, 
magnesia  14-4,  lime  14-9  —  100. 

Hornblende.  Black  and  greenish  black  crystals  and  mas- 
sive specimens.  Often  in  slender  crystallizations  like 
actinolite;  also  short  and  stout  like  Figs.  4  and  5,  the  latter 
more  especially.  Contains  a  large  percentage  of  iron  oxide, 
and  to  this  owes  its  dark  color.  A  tough  mineral  especially 
when  massive,  as  is  implied  in  the  name  it  bears.  Pargasite 
and  hornblende  contain  both  alumina  and  iron.  Composi- 
tion: Silica  48*8,  alumina  7 '5,  magnesia  13*6,  lime  10*2, 
iron  protoxide  18  8,  manganese  protoxide  1-1  =  100. 

BergamasJcite.  A  variety  containing  no  magnesia.  From 
Bergamo. 

Obs.  An  essential  constituent  of  certain  rocks,  as  syenyte, 
dioryte,  and  hornblende  schist.  Actinolite  is  usually  found 
in  magnesian  rocks,  as  talc,  steatite  or  serpentine;  tremo- 
lite  in  crystalline  dolomite;  asbestus  in  the  above  rocks  and 
also  in  serpentine.  The  pyroxene  of  some  Archaean  and 
igneous  rocks  has  been  found  to  be  often  changed  through- 
out to  hornblende  (uralite).  The  two  species  differ  in 
crystallization,  and  not  in  composition;  and  pyroxene  is  the 
less  stable  form  of  the  two.  See  p. 

Black  crystals  of  hornblende  occur  at  Franconia,  N.  H., 
Chester,  Mass.;  Thomastown,  Me.;  Willsboro',  N.  Y.; 
Orange  Co.,  N.  Y.;  and  elsewhere.  Pargasite,  at  Phipps- 
burg  and  Parsonsfield,  Me. ;  glassy  actinolite,  in  steatite  or 
talc,  at  Windham,  Readsboro',  and  New  Fane,  Vt. ;  Middle- 
field  and  Blanford,  Mass.;  and  radiated  varieties  at  the 
same  localities  and  many  others.  Tremolite  and  gray 
hornblende  occur  at  Canaan,  Ct. ;  Sheffield,  Lee,  Monterey, 
Mass.;  Thomaston  and  Raymond,  Me.;  Dover,  Kings- 
bridge,  and  New  York  Island,  N.  Y.;  at  Chestnut  Hill, 
Pa. ;  at  the  Bare  Hills,  Md.  Asbestus  at  many  of  the  above 
localities;  also  Brighton  and  Sheffield,  Mass.;  Cotton  Rock 


BISILICATES.  273 

and  Hustis's  farm,  Phillipstown,  N.  Y. ;  Rabun  and  Fulton 
Cos.,  Ga.  (where  it  is  mined);  Western  N.  Carolina;  San 
Bernardino  and  San  Diego  and  Calaveras  Cos.,  Cal.; 
Province  of  Quebec,  Canada  (where  it  is  mined,  and  is  of 
excellent  quality).  Mountain  leather  is  met  with  at 
Brunswick,  N.  J.  Edenite,  a  white  aluminous  kind,  occurs 
at  Edenville,  N.  Y. 

Asbestus  is  the  only  variety  of  this  species  used  in  the 
arts.  The  flax-like  variety  is  sometimes  woven  into  fire- 
proof textures.  Its  incombustibility  and  slow  conduction 
of  heat  render  it  a  complete  protection  against  the  flames. 
It  is  often  made  into  gloves.  A  fabric  when  dirty  need 
only  be  thrown  into  the  fire  for  a  few  minutes  to  be  white 
again.  The  ancients,  who  were  acquainted  with  its  prop- 
erties, are  said  to  have  used  it  for  napkins,  on  account  of 
the  ease  with  which  it  was  cleaned.  It  was  also  the  wick  of 
the  lamps  in  the  ancient  temples;  and  because  it  maintained 
a  perpetual  flame  without  being  consumed,  they  named  it 
asbestos,  unconsumed.  It  is  now  used  for  the  same  pur- 
pose by  the  natives  of  Greenland.  The  name  amianthus 
alludes  to  the  ease  of  cleaning  it,  and  is  derived  from 
amiantos,  undefiled.  Asbestus  is  extensively  used  for  lin- 
ing iron  safes,  and  for  protecting  steam  pipes  and  boilers. 
About  1600  tons  of  asbestus  were  used  in  the  II.  States  in 
1882;  the  average  price  $30  per  ton.  The  Canadian  is  the 
best,  and  brings  $25  to  $90  to  the  ton.  It  is  obtained  also 
in  Italy  and  Australia.  The  most  of  that  used  is  serpen- 
tine. 

Anthophyllite.  Related  in  the  angle  of  its  prism  to  hornblende,  but 
orthorhombic  ;  in  composition,  and  infusibility  B.B.,  near  bronzite  ; 
B.B.  becomes  magnetic.  Kongsberg,  Modum,  Norway.  Silfbergite 
is  a  manganesian  variety  of  anthophyllite. 

Kupfferite  has  the  hornblende  angle,  but  in  composition  is  like 
enstatite,  being  a  magnesian  silicate. 

Arfvedsonite.  Near  hornblende;  but  contains  over  10  per  cent,  of 
soda,  like  acmite.  Greenland;  Norway;  El  Paso,  Col. 

Crocidolite.  Near  arfvedsonite  in  composition  ;  lavender- blue  to 
leek-green  ;  fibrous.  Orange  River,  South  Africa ;  the  Vosges ; 
Rhode  Island.  Silicified  crocidolite  containing  some  liinoiiite,  now 
common  in  polished  specimens,  is  called  tiger  stone. 

Glaucophane.  A  bluish  mineral  with  the  amphibole  angle.  Island 
of  Syra ;  Zermatt ;  N.  Caledonia.  WicJttisite  may  be  the  same 
species.  Oastaldite  is  a  related  mineral  from  Aosta.  . 

Milante.    Hexagonal;  composition (KH)Ca2AlO32Sii2;  being  a  qua- 
tersilicate  instead  of  a  bisilicate.    Val  Giuf,  Graubiinden  (Grisons). 
18 


274  DESCRIPTIONS   OF  MINERALS. 


Beryl. — Emerald. 

Hexagonal.  In  hexagonal  prisms;  0  on  1  (plane  on  edge 
0:1)  =  150°  3'.  Cleavage  basal,  not  very 
distinct.  Rarely  massive. 

Color  green,  pale  blue  and  yellow,  emerald- 
green.  Streak  uncolored.  Lustre  vitreous; 
sometimes  resinous.  Transparent  to  sub- 
translucent.  Brittle.  H.  =  7 '5-8.  G.  = 
2-67-2-75. 

VARIETIES.  The  emerald  is  the  rich  green  variety ;  it 
owes  its  color  to  the  presence  of  chromium.  Beryl  includes 
the  paler  varieties,  which  are  colored  by  iron.  Aquamarine 
includes  clear  beryls  of  a  sea-green,  pale-bluish  or  bluish- 
green  tint.  Golden  emerald  has  a  rich  yellow  color. 

Composition.  B-eAl3018Sie  with  basic  hydrogen  in  place 
of  a  sixth  atomically  of  the  beryllium.  The  beryl  of  Hebron 
afforded  Silica  62-10,  alumina  18-92,  beryllium  oxide  16-35, 
iron  protoxide  0-47,  caesium  oxide  2 -93,  soda  1'82,  lithia 
1-17,  lime  0-35,  water  2-33  =100-45.  Other  varieties  fail  of 
caesium  and  lithium.  Emerald  contains  less  than  one  per 
cent,  of  chromium  oxide.  B.B.  becomes  clouded,  but  does 
not  fuse;  at  a  very  high  temperature  the  edges  are  rounded. 
Unacted  upon  by  acids.  Rosterite  is  a  variety  from  Elba. 
Pseudo-smaragdite  is  altered  beryl. 

Diff.  The  hardness  distinguishes  this  species  from  apa- 
tite; and  this  character,  and  also  the  form  of  the  crystals, 
from  green  tourmaline. 

Obs.  Found  in  granite,  gneiss,  mica  schist.  Fine  emer- 
alds occur  at  Muso,  near  Santa  Fe,  in  New  Granada,  in 
dolomite;  one  crystal,  2£  in.  long  and  about  2  in  diameter, 
is  in  the  cabinet  of  the  Duke  of  Devonshire;  another  more 
splendid  specimen,  weighing  only  6  oz.,  formerly  in  the 
possession  of  Mr.  Hope,  of  London,  cost  £500.  Emeralds 
of  less  beauty  and  great  size  occur  in  Siberia;  one  in  the 
royal  collection  of  Russia  is  4£  inches  in  length  and 
12  in  breadth,  and  weighs  16f  pounds  troy;  another  is  7 
inches  long  and  4  broad,  and  weighs  6  pounds.  Mount 
Zalora  in  Upper  Egypt  affords  a  less  distinct  variety.  Some 
fine  emeralds  have  been  obtained  at  the  Stony  Point  Mine, 
in  Alexander  Co.,  N".  C.;  one  crystal  was  nearly  10  in. 
long. 


TTNISIL1CATES.  275 

The  finest  beryls  (aquamarine*)  come  from  Siberia,  Hin- 
dostan,  and  Brazil.  One  specimen  belonging  to  Dom  Pedro 
is  as  large  as  the  head  of  a  calf,  and  weighs  225  ounces,  or 
more  than  18J  pounds  troy;  it  is  transparent  and  without  a, 
flaw.  In  1827  a  fine  aquamarine,  weighing  35  grams,  was 
found  in  Siberia,  which  is  said  to  have  been  valued  at 
600,000  francs. 

In  the  U.  States  beryls  of  enormous  size  have  been  ob- 
tained, but  seldom  transparent  crystals.  One  hexagonal 
prism  from  Graf  ton,  N.  H.,  weighing  2900  Ibs.,  4ft.  long 
and  32  by  22  inches  in  its  diameters,  was  of  a  bluish  green 
color,  with  part  of  one  extremity  dull  green  and  yellow. 
The  finest  crystals,  some  good  for  gems,  have  been  found 
at  Stoneham,  Me.;  also  at  Albany,  Norway,  Bethel,  and 
elsewhere,  Me. ;  fine  at  Koyalston,  Mass. ,  formerly  fine  at 
Haddam,  Ct.;  also  at  Avondale  mines,  Delaware  Co.,  Pa.; 
near  Morgantown,  and  elsewhere,  Burke  Co.,  and  Kay's 
Mine,  Yancey  Co.,  and  elsewhere,  N;  C.  Other  localities  are 
Barre,  Fitchburg,  Goshen,  Mass. ;  Wilmot,  N".  H. ;  Grafton, 
Vt.;  Monroe,  Portland,  Ct.;  Leiperville,  Chester,  Upper 
Providence,  Middletown,  Concord,  Marple,  Pa. 

Phenacite.  A  rhombohedral  beryllium  silicate,  in  colorless  and 
yellowish  crystals,  with  H.  =  7 '5-8  and  G.  =  3.  The  Urals;  Switzer- 
land; Durango,  Mexico;  Pike's  Peak,  Col.,  one  3  in.  across;  Florissant 
topaz  loc.  Col. 

Bertrandite  is  related  to  phenacite  in  composition.  It  is  orthorhom- 
bic,  with  I  A  1  —  121°  20';  colorless  or  yellowish;  G.  =  2'59.  From 
near  Nantes,  France. 

Eudialyte.  Pale  rose-red,  crystals  of  rhombohedral  form,  containing 
15 '6  per  cent,  of  zirconia.  From  West  Greenland.  Eucolite  of  Nor- 
way is  here  included. 

Pollucile.  Isometric.  White,  with  vitreous  lustre,  and  G.  =  2'868. 
A  ccBsium  silicate.  Analysis  afforded  Rainmelsberg  Silica  48 '15,  alu- 
mina 16'31,  potash  0'47,  soda  2'48,  caesium  oxide  30'00,  water  2'59  = 
100,  giving  very  nearly  the  bisilicate  formula  H2Cs2AlO1BSi5.  Elba. 

Cappelem'le.  Yttrium  silico-borate;  hexagonal;  brown;  G.  =  4'4. 
Norway. 

II.  UNISILICATES. 

For  the  convenience  of  the  student,  the  general  formulas 
of  the  regular  Unisilicates  are  here  re-stated.  They  are  as 
follows : 

If  the  base  is  in  the  protoxide  state  alone,  the  formula  is 
Ra04Si  (=  2EO  -f  SiO,),  in  which  K  stands  for  Ca,  Mg,  Fe, 


276 


DESCRIPTIONS  OF  MINERALS. 


Mn,  K2,  Na2,  or  Li2,  or  other  mutually  replaceable  base. 
In  analyses,  the  mineral  is  resolved  into  protoxides  and 
silica,  in  the  ratio  of  2RO  to  Si02,  in  which  the  oxygen  of 
the  silica  equals  that  of  the  basic  portion. 

If  the  base  is  in  the  sesquioxide  state  alone,  the  formula 
is  &2O12Si3  (=2R03-f3Si02),  in  which  B  may  stand  for 
Al,  ¥e,  or  Mn,  etc.  Here  the  mineral  is  resolved,  in  analy- 
ses, into  sesquioxides  and  silica  in  the  ratio  of  2R03  to  3Si02, 
in  which  the  oxygen  of  the  silica  again  equals  that  of  the 
basic  portion. 

If  the  basic  portion  is  partly  in  the  protoxide  state  and 
partly  in  the  sesquioxide,  the  formula,  in  its  most  general 
form,  is  (R3,  R)2012Sia.  In  this  formula  the  ratio  of  R3  to 
R  is  not  stated,  If  the  ratio  is  1  : 1,  the  formula  becomes 
R3R012Si3,  or  its  equivalent  (-^R^R)2012Si3.  In  a  case  like 
this  last,  the  mineral  is  resolved,  in  analyses,  into  protoxides, 
sesquioxides,  and  silica,  in  the  ratio  of  3RO  :  R03 :  3Si02, 
in  which  again  the  oxygen  of  the  bases  equals  that  of  the 
silica. 

If  the  proportion  of  R3  to  R  is  1 :  3,  this  corresponds  to 
£R3 :  R,  or,  its  equivalent,  R  :  R;  and  hence  the  formula  in 
its  general  form  will  be  RR08Si2. 

If  the  base  is  in  the  dioxide  state,  the  formula  becomes 
R04Si  (=  R02  -f-  Si02),  an  example  of  which  occurs  in  zir- 
con, whose  formula  is  ZrO^Si. 

There  are  several  natural  groups  of  species  among  the 
Unisilicates. 


GROUP. 

1.  Chrysolite  group, 

2.  Willemite  group, 

3.  Garnet  group, 

4.  Zircon  group, 

5.  Idocrase  and  Sca- 

pblite  groups, 

6.  Mica  group, 

7.  Feldspar  group, 


STATE   OP  BASES. 

protoxide, 
protoxide, 
protoxide  and  sesqui- ) 

oxide,  j" 

dioxide, 
protox.       and 

quiox. 


protox.  and  sesquiox 


protox. 
quiox. 


and 


•i 


ses- 


CRYSTALLIZATION. 

Orthorhombic. 
Hexagonal. 

Isometric. 

Tetragonal. 

Tetragonal. 

Orthorhombic ;  plane 
angle  of  base,  120°; 
micaceous. 

Monoclinic  or  triclin- 
ic,  /A  /nearly  120°. 


In  the  Scapolite,  Mica,  and  Feldspar  groups  part  of  the 
species  contain  an  alkali  metal  in  the  basic  portion,  and 
such  kinds  have  generally  an  excess  of  silica.  Among  the 
feldspars,  the  species  containing  only  calcium  as  the  pro- 


UNISILICATES.  277 

toxide  base  is  a  true  unisilicate.  In  the  others,  there  is  an 
excess  directly  proportional  to  the  increase  of  the  soda,  as 
explained  beyond. 

Chrysolite.— OHvine.     Peridot. 

Orthorhombic.  In  rectangular  prisms  having  cleavage 
parallel  with  i-i.  Usually  in  imbedded  grains  of  an  olive- 
green  color,  looking  like  green  bottle-glass;  also  yellowish 
rn.  Lustre  vitreous.  Transparent  to  translucent. 
=  6-7.  G.  =  3-3-3-6. 

Composition.  (Mg,  Fe)204Si  (or  2  (Mg,  Fe)  0  +  Si02)  =, 
for  a  common  variety,  Silica  41-39,  magnesia  50  '90,  iron 
protoxide  7*71  =  100.  The  amount  of  iron  is  variable. 
B.B.  whitens  but  is  infusible;  with  borax,  a  yellow  bead 
owing  to  the  iron  present.  Decomposed  by  hydrochloric 
acid,  and  the  solution  gelatinizes  when  evaporated.  Hya- 
losiderite  is  a  very  ferruginous  variety  which  fuses  B.B. 

Diff.  Distinguished  from  green  quartz  by  its  occurring 
disseminated  in  basaltic  rocks,  which  never  so  occurs;  and 
in  its  cleavage.  From  obsidian  or  volcanic  glass  it  differs 
in  its  infusibility. 

Obs.  Occurs  as  a  rock  formation;  also  in  a  large  part  of 
the  basalt  of  volcanic  regions,  and  also  in  some  andesyte,  in 
various  cquntries.  As  a  rock  it  occurs  in  N.  Carolina  and 
Pennsylvania;  and  as  a  constituent  of  basalt  in  the  eruptive 
regions  of  the  Pacific  slope,  and  sparingly  in  the  trap  (basalt) 
of  New  Jersey,  New  Hampshire,  etc.  Boltonite,  from  lime- 
stone at  Bolton,  Mass. ,  is  a  variety  of  chrysolite.  It  also 
occurs  in  many  meteorites. 

Sometimes  used  as  a  gem,  but  too  soft  to  be  valued,  and 
not  delicate  in  its  shade  of  color. 

Forsterite  is  a  magnesian  chrysolite  Mg2O4Si;  Fayalite,  an  iron  chrys- 
olite, Fe2O4Si,  and  fusible,  a  rather  common  variety,  occurring  occa- 
sionally in  crystals  as  in  the  obsidian  of  Yellowstone  Park;  Monticel- 
lite,  a  calcium  magnesium,  CaMg2O48i;  Hortonolite,  an  iron  magnesium 
manganese  chrysolite  from  Orange  Co.,  N.  Y.;  Hoepperite,  an  iron- 
mangancse-zinc  chrysolite  from  Stirling  Hill,  N.  J. ;  Tephroite,  a  man- 
ganese chrysolite,Mn2O4Si,  from  Stirling  Hill,  N.  J. ;  Kwbelite&  man- 
ganese-iron chrysolite,  MnFeO4Si,  from  Dannemora.  Igelslromile  (of 
M.  Weibull)  is  near  Knebelite.  Neochrysolite,  from  Vesuvius,  contains 
some  manganese. 

CuspidHe.  In  rose  reel  spear-shaped  monoclinic  crystals;  H.  =  5'6; 
G.  =  2'85-2'86.  Contains  silica,  lime,  fluorine.  From  Vesuvius. 

Leucophanite  and  MdipJianite.    Contain  the  element  beryllium;  the 


278  DESCRIPTION'S   OF   MINERALS. 

former,  greenish  yellow,  and  G.  =  2 '97;  the  latter,  yellow  and  G.  = 
3-018.  Norway. 

Wolilerite.  Contains  zirconium  and  also  niobium;  color  light 
yellow;  G.  =  3'41. 

Willemiie.    Zinc  unisilicate,  Zn2O4Si.     See  page  173. 

Dioptase.  Copper  silicate,  which,  making  the  water  basic,  is  a  uni- 
silicate, H2CuO4Si.  See  page  156.  The  Kirghese  Steppes;  Chili. 

FriedeWe.  Rose-red  manganese  silicate,  of  the  general  formula 
R2O4Si,  in  which  R  consists  of  manganese  and  hydrogen  in  the  atomic 
ratio  2:1.  The  Pyrenees. 

Helmte  (Helvin).  Isometric ;  in  tetrahedral  crystals;  color  honey- 
yellow,  brownish,  greenish;  lustre  vitreo-resinous;  H.  =  6-6 '5;  G.  = 
3*l-3'3;  contains  manganese,  iron  and  beryllium,  and  some  sulphur. 
Saxony;  Norway;  Amelia  Co.,  Va. 

Danalite.  Isometric;  in  octahedral  crystals;  color  flesh-red  to  gray; 
lustre  vitreo-resinous;  H.  —  5'5;  G.  =  3'427;  contains  zinc,  beryllium, 
iron,  manganese.  Disseminated  through  granite  at  Rockport,  Cape 
Ann,  Mass. ;  near  Gloucester,  Mass. ;  Bartlett,  N.  H. 

EulytHe.  A  bismuth  silicate  f  rom  Johanngeorgenstadt. 

Bismuto-ferrite.     A  bismuth-iron  silicate. 

Peckhamite.    In  nodules  in  an  Iowa  meteorite. 

Garnet. 

Isometric.  Dodecahedrons  (Fig.  1)  and  trapezohedrons 
(Fig.  2);  both  forms  are  common,  and  are  sometimes  vari- 
ously modified.  Cleavage  parallel  to  the  faces  of  the  dode- 
cahedron sometimes  rather  distinct.  Also  found  massive 
granular,  and  coarse  lamellar. 

Color  deep  red  to  cinnamon  color;  also  brown,  black, 


1. 


green,  emerald-green,  rarely  colorless.  Transparent  to 
Upaque.  Lustre  vitreous.  Brittle.  H.  =6 '5-7*5.  G.  = 
3 -1-4-3. 

Composition  and  Varieties.  General  formula  R3RO]2Si3; 
in  which  R  may  be  calcium,  magnesium,  iron,  manganese, 
and  B  may  be  aluminium,  iron,  chromium.  The  varieties 
owe  their  differences  to  the  proportions  of  these  elements, 
or  the  substitution  of  one  for  another.  Most  garnets  fuse 
easily  B.B.  to  a  brown  or  black  glass;  but  the  fusibility 


UNISILICATES.  279 

varies,  and  chrome-garnet  is  infusible.  Not  decomposed 
by  hydrochloric  acid;  but  if  first  ignited,  then  pulverized 
and  treated  with  acid,  they  are  decomposed,  and  the  solu- 
tion usually  gelatinizes  when  evaporated. 

There  are  three  series  among  the  varieties:  one,  that  of 
alumina-garnet,  in  which  the  sesquioxide  base  is  chiefly 
aluminium;  the  second,  that  of  iron-garnet,  in  which  the 
sesquioxide  base  is  chiefly  iron  instead  of  aluminium;  and 
third,  chrome-garnet,  in  which  it  is  chromium. 

I.  ALUMINA-GARNET. 

Almandite  (Almandine).  An  iron  alumina-garnet,  Fe3 
A101QSi3  =  Silica  361,  alumina  20*6,  iron  protoxide  43 '3  = 
100.  G.  =  3 '8-4*25.  Of  various  shades  of  red,  ruby-red, 
hyacinth-red,  columbine-red,  brownish  red.  If  transparent, 
called  precious  garnet;  if  not  so,  com mo  ^  "garnet. 

Grossularite  (including  Cinnamon  Stone,  Essonite,  Suc- 
cinite). A  lime  alumina-garnet,  Ca3A1012Si3  =^  Silica  401, 
alumina  22*7,  lime  37*2  —  100,  but  often  with  some  iron 
protoxide  in  place  of  part  of  the  lime.  G.  =3 '4-3*75. 
Grossularite  is  pale  green,  and  was  hence  named  from  the 
Latin  for  gooseberry.  Cinnamon  Stone  or  Essonite  is  cin- 
namon-colored. Succinite  is  amber-colored. 

Pyrope.  A  magnesia  alumina-garnet  Mg3A1012Sis. 
Color  deep  red,  but  varying  to  black  and  green.  G.  —  315 
-38. 

Spessartite.  A  manganese  alumina-garnet  (Mn,  Fe)3Al 
0]2Si3,  some  iron  replacing  part  of  the  manganese.  Color 
red,  brownish  red,  hyacinth-red.  G.  =  mostly  4-4*4.  A 
Haddam  specimen  afforded  Silica  35 '8.  alumina  181,  iron 
protoxide  14*9,  manganese  protoxide  31*0. 

II.  IKON-GARNET. 

Andradite.  A  lime  iron-garnet,  Ca3Pe012Si3.  Colors 
various,  from  that  of  almandite  or  common  garnet,  to  a 
wine-yellow,  as  in  Topazotite;  green,  as  in  Jeltctite;  and 
black,  as  in  Metanite  and  Pyreneite.  G.  =  3 '64-4. 

Colophonite.  A  dark  red  to  brownish  yellow  coarse  gran- 
ular garnet  having  often  iridescent  hues. 

Aplome.     A  red  variety. 

Rothoffite.  Has  manganese  in  place  of  part  of  the  lime, 
and  a  yellowish  brown  to  reddish  brown  color. 

Ytter -garnet.  Contains  yttria  in  place  of  part  of  the 
lime. 

Bredbergite.     A  lime-magnesia  iron-garnet. 


280  DESCRIPTIONS   OF  MINERALS. 

III.  CHROME-GARNET. 

Ouvarovite.  An  emerald-green  lime  chrome-garnet,  Ca3 
CraO]3Si8,  with  some  alumina.  G.  =  3 -41-3 '52. 

Diff.  The  vitreous  lustre  of  fractured  garnet,  and  its 
usual  dodecahedral  and  trapezohedral  forms,  are  easy  char- 
acters for  distinguishing  it. 

Obs.  Occurs  abundantly  in  mica  schist,  hornblende  schist, 
and  gneiss,  and  somewhat  less  frequently  in  granite  and 
granular  limestone;  sometimes  in  serpentine;  occasionally  in 
trap,  and  other  igneous  rocks.  A  massive  buff-colored  gar- 
net, occurring  in  thin  layers,  in  hydromica  (sericite)  schist, 
in  Belgium,  is  the  material  of  the  finest  of  razor-stones. 

The  best  precious  garnets  are  from  Ceylon  and  Green- 
land; cinnamon  stone  comes  from  Ceylon  and  Sweden;  gros- 
sularite  occurs  in  the  Wilui  River,  Siberia,  and  at  Tellemar- 
ken  in  Norway;  green  garnets  are  found  at  Schwartzenberg, 
Saxony;  melanlte,  in  the  Vesuvian  lavas;  ouvarovite,  at  Bis- 
sersk  in  Russia;  topazolite,  at  Mussa,  Piedmont. 

In  the  U.  States,  fine  clear  red  crystals  occur  in  Delaware 
Co.,  Pa.;  Stony  Point,  N.  C.  Crystals  of  a  dark-red^  color, 
of  small  size  at  Hanover,  !N".  H. ;  large,  some  1^  in.,  at 
Haverhill  and  Springfield,  N.  H. ;  large  at  New  Fane,  Vt. ; 
at  Unity,  Brunswick,  Streaked  Mountain,  Albany,  etc., 
Me.,  some  of  the  Albany  garnets  weighing  each  20  Ibs. ;  at 
Monroe,  Lyme,  and  Redding,  Ct.;  Bedford,  Chesterfield, 
Barre,  Brookfield,  and  Brimfield,  Mass. ;  very  large  and  fine 
at  Russell,  Mass.;  Roger's  Rock,  Essex  Co.,  N.  Y.;  Frank- 
lin, 1ST.  J.;  Avondale,  Chester,  Darby,  and  elsewhere,  Pa.; 
Burke,  Caldwell,  and  Catawba  Cos.,  N".  C.,  especially  fine 
8  m.  S.  E.  of  Morgantown,  and  near  Warlick,  in  Burke  Co. ; 
large  and  fine  in  Alaska,  near  Ft.  Wrangel.  Essonite  at 
Carlisle  and  Boxborough,  Mass.;  with  idocrase  at  Parsons- 
field,  Phippsburg  and  Rumford,  Me.;  Amherst,  N.  H.; 
Amity,  N.  Y. ;  Franklin,  Sussex  Co.,  N.  J. ;  Dixon's 
Quarry,  seven  miles  from  Wilmington,  Del.,  in  fine  trapezo- 
hedrons.  Grassulariie,  Good  Hope  mine,  Cal. ;  Gila  Canon, 
Arizona.  Melanite,  at  Franklin,  N.  J.,  and  Germantown, 
Pa.  Ouvarovite,  at  "Wood's  chrome-mine,  Lancaster  Co., 
Pa. ;  Orf  ord  and  Wakefield,  Canada.  Colophonite,  at  Wills- 
borough  and  Lewis,  Essex  Co.,  N.  Y.;  N.  Madison,  Conn. 
Colorless  at  Hull,  Canada.  • 

Garnet  is  the  carbuncle  of  the  ancients.  The  alabandic 
carbuncles  of  Pliny  were  so  called  because  cut  and  polished 


UNISILICATES. 


281 


at  Alabanda,  and  hence  the  name  Almandine  now  in  use. 
The  garnet  is  also  supposed  to  have  been  the  hyacinth  of 
the  ancients. 

Clear  deep-red  garnets  make  a  rich  gem,  and  are  much 
used;  those  of  Pegu  are  most  valued.  They  are  cut  thin, 
on  account  of  their  depth  of  color.  Cinnamon-stone  is 
also  employed  for  the  same  purpose.  Powdered  garnet  is 
sometimes  used  as  emery.  Pliny  describes  vessels,  of  the 
capacity  of  a  pint,  formed  from  large  carbuncles,  "  devoid 
of  lustre  and  transparency,  and  of  a  dingy  color,"  which 
probably  were  large  garnets. 

Zircon. 

Tetragonal ;  /  f\l  =  132°  10';  1  Al  =123°  19'.     Cleav- 

;e  parallel  to  /,  but  imperfect.  Usually  in  crystals;  but 
so  granular. 

1.                   2.  3.                4. 


Color  brownish  red,  brown,  and  red,  of  clear  tints;  also 
yellow,  gray,  and  white.  Streak  uncolored.  Lustre  more 
or  less  adamantine.  Often  transparent;  also  nearly  opaque. 
Fracture  conchoidal,  brilliant.  H.  =  7*5.  G.  of  purest 
crystals  =  4 -6-4 '86,  but  varies  from  4-4*9. 

Composition.  Zr04Si  (=  2ZrO  -f  Si02)  =  Silica  33,  zir- 
conia  67  =  100.  B.B.  infusible,  but  loses  color. 

VARIETIES.  Transparent  red  specimens  are  called  hya- 
cinths'; colorless,  from  Ceylon,  having  a  smoky  tinge,  jar- 
gon (sold  for  inferior  diamonds,  which  they  resemble, 
though  much  less  hard).  Gray  and  brownish  varieties 
sometimes  called  zirconite. 

Diff.  Readily  distinguished  from  species  which  it  resem- 
bles by  its  crystals,  specific  gravity,  and  adamantine  lustre. 

Obs.  Confined  to  crystalline  rocks,  occurring  in  granite, 
granulyte,  gneiss,  granular  limestone,  and  some  igneous 
rocks.  Zircon- syenyte  is  an  elaeolite-syenyte  with  dissemi- 
nated zircons.  Crystals  often  occur  in  auriferous  sands. 
Hyacinth  occurs  mostly  in  grains  in  such  sands,  and  comes 
from  Ceylon;  Auvergne,  Bohemia,  and  elsewhere  in  Europe. 


282 


DESCRIPTIONS  OF  MINERALS. 


Siberia  affords  large  zircons.  Fine  specimens  come  from 
Greenland.  Beccarite  is  an  olive-green  var.  from  Ceylon. 

In  the  United  States,  gray  crystals  occur  in  Buncombe 
Co.,  N".  C. ;  and  common  in  the  gold  sands  of  Polk,  Mc- 
Dowell, Rutherford,  and  other  cos.,  N.  C.;  cinnamon-red 
in  Moriah,  Essex  Co.,  Two  Ponds  and  elsewhere,  Orange 
Go.,  Hammond,  St.  Lawrence  Co.,  and  Johnsbury,  Warren 
Co.,  N.  Y.;  Franklin,  N.  J.;  Litchfield,  Me.;  Middlebury 
Vt. ;  fine  near  the  Pike's  Peak  toll-road,  due  west  of  the 
Cheyenne  Mts. ;  also  elsewhere  in  the  Pike's  Peak  region. 
Canada,  at  Grenville,  etc.,  also  in  Renfrew  Co.,  one  crystal 
reported  nearly  10  in.  long  and  4  in.  through,  weighing  12 
pounds. 

Named  hyacinth  from  the  Greek  huakinthos;  but  it  is 
doubtful  whether  the  ancients  so  called  stones  of  the  zircon 
species. 

The  clear  crystals  (hyacinths)  are  of  common  use  in 
jewelry.  When  heated  in  a  crucible  with  lime,  they  lose 
their  color,  and  resemble  a  pale  straw-yellow  diamond,  for 
which  they  are  substituted.  Zircon  is  also  used  in  jewelling 
watches.  The  hyacinth  of  commerce  is  to  a  great  extent 
cinnamon-stone,  a  variety  of  garnet.  The  earth  zirconia 
is  used  as  an  advantageous  substitute  for  lime  in  the  oxyhy- 
drogen  lantern. 

Auerbachite,  Malacon,  TachyapJialtite,  (Erstedite,  Bragite,  are  names 
of  zircon-like  minerals  supposed  to  be  zircon  partly  altered.  Almte  is 
similar  in  form  to  zircon.  Heldburgite  is  probably  near  zircon. 

Lovenite.  Zirconium-calcium-sodium  silicate;  monoclinic;  brown, 
yellowish.  Norway. 

The  earth  zirconia  is  also  found  in  the  rare  minerals  eudialyte  and 
wohlerite;  also  in  polymignite,  ceschynite;  also  sparingly  in  fergusonite. 


V 


Tetragonal. 


1. 


Vesuvianite. — Idocrase. 
0  A  1  =  142°  46';  1  A  1  =  129°  21',  1 


3. 


=  127°  14'.     Cleavage  not  very  distinct  parallel  with  /. 
Also  massive  granular,  and  subcolumnar. 


UtflSILICATES.  283 

Color  brown;  sometimes  passing  into  green.  Some  va- 
rieties oil-green  in  the  direction  of  the  axis  and  yellowish 
green  transverse  to  it.  Streak  uncolored.  Lustre  vit- 
reous. Subtransparent  to  nearly  opaque.  H.  —  6*5.  G.  = 
3-33-3-4. 

Composition.  (4Ca3f  Al)201QSi3.  A  small  part  of  the  Ca 
is  usually  replaced  by  magnesium,  and  part  of  the  aluminium 
sometimes  by  iron  in  the  sesquioxide  state.  Percentage  of 
&  common  variety,  Silica  37'3,  alumina  16  •!,  iron  sesquiox- 
ide 3 '7,  lime  3 5  4,  magnesia  2'1,  iron  protoxide  2  -9,  water 
2'1  =  99*6.  B.B.  fuses  easily  with  effervescence  to  a  green- 
ish or  brownish  globule. 

Diff.  Resembles  some  brown  garnet,  tourmaline  and 
epidote,  but  differs  in  crystallization,  and  in  greater  fusi- 
bility. 

Obs.  First  found  in  the  lavas  of  Vesuvius,  and  hence  the 
name.  Occurs  in  Piedmont;  near  Christiania,  Norway;  in 
Siberia;  in  the  Fassa  Valley.  Cyprine  includes  blue  crys- 
tals from  Tellemarken,  Norway;  supposed  to  be  colored  by 
copper. 

In  the  IT.  States,  in  fine  crystals  at  Phippsburg  and  Rum- 
ford,  Sandford,  Parsonsfield  and  Poland,  Me.;  Newton, 
N.  J. ;  Amity,  N.  Y. ;  in  Canada  at  Calumet  Falls,  and  at 
Grenville. 

Named  from  the  Greek  eido,  to  see,  and  Jcrasis,  mixture; 
because  its  crystalline  forms  have  much  resemblance  to 
those  of  some  other  species. 

Sometimes  cut  as  a  gem  for  rings. 

Mellilite  in  honey-yellow  crystals  (which  includes  Hum- 
boldtilite),  is  a  related  tetragonal  species,  from  Capo  di  Bove, 
near  Rome  and  Mount  Somma,  Vesuvius. 

Epidote. 

Monoclinic;  0  =  89°  27';  i-i  A  l-i  =  115°  24',  i-i A —I-i 
=  116°  18',  - 1  A  -1  =  109°  35'. 
Cleavage  parallel  to  i-i ;  less  dis- 
tinct parallel  to  I-i.  Also  mas- 
sive granular  and  forming  rock 
masses;  sometimes  columnar  or 
fibrous. 

Color  yellowish  green  (pista- 
chio-green) and  ash-gray  or  hair-brown.    Trichroic.   Streak 
uncolored.     Translucent   to    opaque.     Lustre  vitreous,   a 


284  DESCRIPTIONS   OF  MINERALS. 

little  pearly  on  i-i ;  often  brilliant  on  the  faces  of  crystals. 
Brittle.    H.  =  6-7.     G.  =  3'25-3-5. 

Composition.  A  lime-iron-aluminium  silicate,  the  iron 
being  mostly  in  the  sesquioxide  state  and  replacing  alu- 
minium, and  the  water  basic;  and  the  hydrogen  to  the  cal- 
cium as  1 :  4.  RBAl3026Si6  =  Silica  37'83,  alumina  22-63, 
iron  sesquioxide  15 '02,  iron  protoxide  0'93,  lime  23 -27, 
water  2-05  =  100-73. 

B.B.  fuses  with  effervescence  to  a  black  glass  which 
usually  is  magnetic.  Partially  decomposed  by  hydrochloric 
acid,  but  if  first  ignited,  is  then  decomposed,  and  the  solu- 
tion gelatinizes  on  evaporation. 

Green  epidote  is  often  called  Pistacite.  Piedmontite  is 
a  variety  containing  much  manganese,  of  reddish  brown  or 
reddish  black  color.  Bucklandite  is  an  iron  epidote. 

Diff.  The  peculiar  yellowish  green  color  of  ordinary  epi- 
dote 'distinguishes  it  at  once.  From  zoisite  and  vesuvianite 
it  differs  in  fusing  to  a  black  magnetic  globule.  The  ash- 
gray  mineral  related  to  epidote  is  mostly  zoisite. 

Obs.  Occurs  in  crystalline  rocks,  especially  in  hornblendic 
rocks.  Often  occurs  in  the  cavities  of  amygdaloidal  rocks. 
In  crystals,  six  inches  long,  and  with  brilliant  faces  and  of 
rich  color,  at  Haddam,  Ct. ;  crystallized  also  at  Franconia, 
N.  H. ;  Hadlyme,  Chester,  Newbury,  and  Athol,  Mass. ;  near 
Unity,  Amity,  and  Monroe,  N".  Y. ;  Franklin,  Warwick, 
and  Eoseville,  N.  J. ;  Pennsylvania,  at  W.  Bradford  and  E. 
Bradford;  Hampton,  Yancey  Co.,  N.  C.;  Michigan,  in  the 
Lake  Superior  region;  Canada,  at  St.  Joseph. 

Named  epidote  by  Haiiy  from  the  Greek  epididomi,  to 
increase,  in  allusion  to  the  fact  that  the  base  of  the  primary 
is  frequently  much  enlarged  in  the  crystals. 

Picroepidote.     Supposed  to  be  a  magnesian  epidote.     Siberia. 

Allanite.  A  cerium  epidote,  the  crystals  similar;  black  to  pinchbeck- 
brown;  lustre  submetallic  to  pitch-like  and  resinous.  H.  =  5*5-6;  G.  = 
3-4'2;  B.B.  fuses  easily  and  swells  up  to  a  dark,  blebby  magnetic  glass; 
most  varieties  gelatinize  with  hydrochloric  acid,  but  not  after  ignition. 
Norway;  Sweden;  Greenland;  Scotland;  Snarum,  near  Dresden;  Tops- 
ham,  Me.;  Bolton  quarry,  Mass.;  Moriah,  Essex  Co.,  Monroe,  Orange 
Co. ,  N.  Y. ;  Franklin,  N.  J. ;  at  East  Bradford  and  Eaton,  Pa. ;  Amherst 
Co. ,  Va. ;  in  Canada,  at  St.  Paul's. 

Orthite.  A  variety  of  allanite  in  long  slender  crystals:  occurs  in 
Amelia  Co. ,  Va. ;  N.  Carolina.  Vasite  is  altered  orthite.  Muromontite, 
Bodenite,  and  Michaelsonite  are  related  minerals. 

&adolinite.    Color  greenish-black;  monoclinic,  with  7  A  /=  116°; 


UNISILICATES.  285 

H.  =  6'5-7;  G.=  4-4-5;  contains  lithium,  cerium,  and  beryllium,  with 
SiO2  25  p.  c.  Sweden;  Greenland;  Norway. 

Rinkite.  Monoclinic ;  yellowish  brown.  Titanium-cerium-lan- 
thanum-calcium silicate,  with  fluorine.  Greenland. 

Mosandrite.  Monoclinic.  Reddish  brown,  dull  greenish,  yellowish 
brown;  H.  =  4;  G.  =  2-9-3'03;  silicate  of  cerium,  lanthanum,  didym- 
ium,  calcium,  and  titanium.  Brevig,  Norway. 

Zoisite.— Lime-Epidote. 

Orthorhombic ;  /  A  I  =  116°  40'.  Cleavage  brachydiag- 
onal,  perfect.  Also  columnar  and  massive. 

Color  ash-gray  to  white;  also  greenish  gray,  red  ( Thulite). 
Lustre  vitreous  to  sub-pearly.  H.  =  6-6.  G.  =  3 -11-3 -38. 

Composition.  Like  epidote,  but  with  little  or  no  iron. 
That  of  Ducktown,  Tenn.,  afforded  Silica  39-61,  alumina 
32-89,  iron  sesquioxide  0-91,  iron  protoxide  0'71,  magnesia 
0-14,  lime  24-50,  water  2-12  =  100-88.  B.B.  swells  up  and 
fuses  to  a  blebby  glass;  gelatinizes  with  hydrochloric  acid 
after  ignition.  Unlike  hornblende  in  its  one  perfect  cleavage. 

Obs.  From  Saualpe,  Carinthia,  in  the  Tyrol;  Arendal, 
etc. ;  Willsboro'  and  Montpelier,  Vt. ;  Goshen,  Chesterfield, 
etc.,  Mass.;  Union ville  and  Leiperville,  Pa.;  Ducktown 
copper- mine,  Tenn. 

Saussurite.  Fine-grained  and  tough;  white,  bluish  or  yellowish  white, 
grayish;  G.  =  3-3 '5.  Eesults  from  the  alteration  of  a  triclinic  feld 
spar,  the  form  or  cleavage  of  which  is  sometimes  retained.  The  chief 
constituent  of  the  euphotide  (p.  )  of  the  Alps,  Mt.  Genevre,  Orezza, 
Corsica.  Hunt  made  the  saussurite  of  the  Alps  (G.  =  3 '36-3  385),  by 
his  analyses,  a  soda-bearing  zoisite  (silica  43'6  and  48"1).  Most  kinds 
are  between  zoisite  and  anorthite  or  labradorite  in  composition,  and 
are  apparently  altered  forms  of  these  feldspars.  Has  been  made  a 
mixture  of  zoisite  and  a  feldspar.  A  kind  from  Wildschonau,  having 
G.  =  3-011,  and  silica  48*3  p.  c.,  is  made  by  Cathrein  such  a  mixture, 
but  more  investigation  is  needed.  Altered  anorthite  crystals  from 
Hanover,  N.  H.,  of  similar  characters,  with  G.  =  2 -96,  have  nearly, 
according  to  Hawes,  the  composition  of  labradorite  (silica  52-52  p.  c.). 
The  high  specific  gravity  separates  the  mineral  from  the  feldspars. 

Arctolite.  Near  zoisite;  G.  =  3 '03.  From  crystalline  limestone. 
Spitzbergen.  Balvraidite,  from  limestone  in  Scotland,  is  of  similar 
composition. 

Ilvaite ( Tenite).  In  orthorhombic  striated  prisms;  /  A  /=  112°  88' ; 
iron-black  to  grayish  black;  H.  =  5  5-6;  G.  —  3'7-4'2.;  in  composition 
a  calcium-iron  silicate  in  which  part  of  the  iron  is  in  the  sesquioxide 
state.  Elba;  Fossum  and  Skeen,  Norway,  etc.  Reported  as  occur- 
ring  at  Cumberland,  R.  I.;  Milk  Row  quarry,  in  Somerville,  Mass.; 
near  Manayunk,  Pa.  Named  Ilvaite  from  the  Latin  name  of  Elba. 

Ardennite.  Near  Ilvaite  in  crystals  and  low  p.  c.  of  silica,  but 
contains  much  manganese  oxide  and  more  or  less  of  vanadium  pent- 
oxide;  G.  =  3 '620;  clear  yellow  to  brown.  Ardennes,  Belgium. 


286  DESCRIPTIONS  OF  MINERALS. 

Barylite.  A  silicate  containing  46 '23  of  baryta;  H.  =  7;  G.  =4*03; 
colorless;  the  oxygen  ratio  for  bases  and  silica  10  :  7,  or  that  of  a  sub- 
silicate.  Longban,  Sweden. 

Axinite. 

Triclinic.      In  acute-edged  oblique  rhomboidal  prisms  ; 
P/\r  =  l34:°   45',    r  /\u  =  115°   38',  PA  u  =  135°   31'. 
Cleavage  indistinct.     Also  rarely  massive  or  lamellar. 
Color  clove-brown;  differing  somewhat  in  shade  in  three 
directions,    being    trichroic.     Lustre  vit- 
reous.     Transparent     to    subtranslucent. 
Brittle.     H.  =  6*5-7.     G.  =  3  "27.     Pyro- 
electric. 

Composition.  A  unisilicate,  containing 
boron.  One  analysis  afforded  Silica  43*68, 
boron  trioxide  5*61,  alumina  15*63,  iron 
sesquioxide  5*45,  manganese  sesquioxide 
3-05,  lime  20*92,  magnesia  1*70,  potash 
0*64  =  100*43.  B.B.  fuses  easily  with  in- 
tumescence to  a  dark  green  or  black  glass, 
imparting  a  pale  green  color  to  the  flame  which  is  due  to 
the  boron. 

Diff.  Remarkable  for  the  sharp  thin  edges  of  its  crystals, 
their  glassy  brilliant  appearance,  and  absence  of  cleavage; 
implanted,  and  not  disseminated  like  garnet.  In  one  or 
all  of  these  particulars,  and  also  in  blowpipe  reaction,  it  dif- 
fers from  any  of  the  titanium  ores. 

Obs.  Occurs  at  St.  Christophe  in  Dauphiny;  Kongsberg 
in  Norway;  Normark  in  Sweden;  Santa  Maria,  in  Switzer- 
land; Cornwall,  England;  Thum  in  Saxony,  whence  the 
name  Thummer stein  and  Tliummite. 

In  the  U.  States,  at  Phippsburg  and  Wales,  Me. ;  Cold 
Spring,  N".  Y.;  Bethlehem,  Pa. 

Danburite. 

Orthorhombicr,  1:1=122°  52';  resembles  topaz  in  its 
crystals.  Also  massive.  Color 
pale-yellow,  honey-yellow.  Trans- 
parent. Lustre  vitreous,  slightly 
greasy  when  massive.  H.  =  7— 
7*25.  G.  =2*986-3*021. 

Composition.  A  calcium-silicate 
containing    much    boron ;    (^Ca3 
f£-)o>  012Sia.     In  an  analysis,  Si03 
48-23,  Ba03  26-93,  Ala03  0*47,  Fea03  tr.,  CaO  23*24,  ign. 


MICA   GROUP.  287 

0'63  =  99 '50.     B.B.  fuses  to  a  colorless  glass;  reaction  for 
boron,  which  distinguishes  it  easily. 

Obs.  From  Danbury,  Ct.;  Russell,  N.  Y.,  in  large  crys- 
tals; Switzerland. 

lolite.— Dichroite.    Cordicrite. 

Orthorhombic ;  /A  /  near  120°.  Commonly  in  .6-  and  12- 
sided  prisms.  Also  massive.  Cleavage  indistinct;  but  crys- 
tals often  separable  into  layers  parallel  to  the  base,  especially 
after  partial  alteration. 

Color  various  shades  of  blue,  looking  often  like  a  pale  or 
dark  blue  glass;  often  deep  blue  in  direction  of  the  axis,  and 
yellowish  gray  transversely.  Streak  uncolored.  Lustre  vit- 
reous. Transparent  to  translucent.  Brittle.  H.  =  7-7  '5. 
G.  =  2-6-2;7. 

Composition.  A  silicate  of  aluminium,  magnesium,  and 
iron,  corresponding  to  Silica  49-4,  alumina  33 '9,  magnesia 
8-8,  iron  protoxide  7'9  =  100.  B.B.  loses  its  transparency; 
fuses  with  much  difficulty. 

Diff.  Eesembles  blue  quartz,  and  is  distinguished  by 
fusing  on  the  edges.  Easily  scratched  by  sapphire. 

Obs.  Found  at  Haddam,  Ct.,  in  granite;  also  in  gneiss 
at  Brimfield,  Mass.;  at  Richmond,  N.  H.;  at  Bodenmais  in 
Bavaria;  Arendal,  Norway;  Capo  de  Gata,  Spain;  Tunaberg, 
Finland;  Norway;  Greenland;  Ceylon. 

Named  from  the  Greek  ion,  violet,  alluding  to  its  color; 
and  dichroile,  from  dis,  twice,  and  chroa,  color,  referring 
to  the  different  colors  in  two  directions. 

Occasionally  employed  as  an  ornamental  stone,  and  is  cut 
so  as  to  present  the  different  shades  of  color  in  different  di- 
rections. 

lolite  exposed  to  the  air  and  moisture  undergoes  a  gradual  altera- 
tion, becoming  hydrous,  and  assuming  a  foliated  micaceous  structure 
so  as  to  resemble  talc,  though  more  brittle  and  hardly  greasy  in  feel. 
Hydrous  lolite,  Fahlunite,  Chlorophyllite,  and  Esmarkite  are  names  that 
have  been  given  to  the  altered  iolite;  and  Gigantolite  and  a  number  of 
other  like  minerals  are  of  the  same  origin.  (See  p.  315.) 

MICA  GROUP. 

The  minerals  of  the  mica  group  are  alike  in  having  (1) 
their  crystals  monoclinic;  (2)  the  front  plane  angle  of  the 
base,  or  of  the  cleavage  laminae,  120°;  (3)  cleavage  eminent, 
parallel  to  the  base,  affording  very  thin  laminae;  and  (4) 
aluminium  %&&  potassium  among  the  essential  constituents; 


288  DESCRIPTIONS   OF   MINERALS. 

sodium  is  often  present,  but  only  one  species,  paragonite, 
contains  sodium  instead  of  potassium.  In  muscovite  and 
paragonite  the  protoxide  elements  are  almost  solely  the 
alkali  metals,  with  hydrogen  (of  the  water  present);  in 
phlogopite,  they  are  potassium  and  magnesium;  in  biotite 
and  some  related  kinds,  potassium,  magnesium,  and  iron; 
in  annite,  potassium  and  iron;  in  cryopKylttte,  much  potas- 
sium and  much  lithium  with  some  iron.  Zinmvaldite  is  near 
the  last.  One,  CEllaclierite,  contains  near  6  p.  c.  of  barium 
with  the  potassium.  Fluorine  is  present  in  most  mica. 

The  combining  or  oxygen  ratio  for  the  bases  (the  water 
being  included)  is  mostly  1  to  1;  but  in  some  kinds  the  sili- 
con is  in  excess,  and  the  ratio  becomes,  at  the  extreme,  1  to 
1^,  as  in  zinnwaldite  and  some  muscovite. 

The  ordinary  light-colored  micas  are  mostly  muscovite, 
and  the  black,  mostly  biotite.  The  optic-axial  plane  in 
most  micas  passes  through  the  longer  diagonal  of  the  base, 
being  perpendicular  to  the  plane  of  symmetry.  In  a  black- 
ish Vesuvian  mica  (meroxene)  and  in  phlogopite  and  zinn- 
waldite, it  passes  through  the  shorter  diagonal  of  the  base. 
Lepidolite  is  a  light -colored  mica  containing  lithia,  belong- 
ing with  muscovite.  Muscovite  and  biotite  are  so  related 
that  crystals  of  the  latter  often  occur  that  are  finished  out 
uninterruptedly  by  muscovite,  the  axial  lines  of  the  one 
continuous  with  those  of  the  other;  and  such  crystals  are 
sometimes  several  inches  across;  there  is  here  a  compound 
structure  chemically,  but  no  twinning  in  the  crystallization. 
When  a  thin  plate  of  mica  is  struck  with  a  pointed  awl  or 
other  like  tool  a  symmetrical  star  of  six  rays  is  produced, 
the  rays  being  cleavage  lines  parallel  to  the  sides  of  the 
rhombic  prism  /  and  the  shorter  diagonal. 

,    .  Muscovite. — Common  Mica. 

Monoclinic.  Usually  in  plates  or  scales.  Sometimes  in 
radiated  groups  of  aggregated  scales 
(plumose  mica);  rarely  spheroidal. 

Colors  from  white  through  green, 
yellowish  and  brownish  shades;  rarely 
rose-red  or  reddish  violet.  Lustre 
more  or  less  pearly.  Transparent  or 
translucent.  Tough  and  elastic. 
H.  =2-2-5.  G.  =2-7-3.  Optic-axial 
angle  44°  to  78°. 
Composition.  A  common  variety  has  the  general  formula 


MICA   GROUP.  289 

(iR3f  R)2012Si3,  R  including  K2  and  H2,  and  R,  aluminium 
and  some  iron  in  the  sesquioxide  state.  An  analysis  of  mica 
of  this  variety  obtained  Silica  4G*3,  alumina  36-8,  iron  ses- 
quioxide 4-5,  potash  9'2,  fluorine  0'7,  water  1*8  =  99 -3;  3 
to  5  p.  c.  of  water  often  present,  and  passes  thus  to  a  hy- 
drous mica.  The  variety  Phengite  contains  more  silica. 
B.B.  whitens  and  fuses  on  the  thinnest  edges  with  difficulty 
to  a  gray  or  yellow  glass.  Some  altered  mica  exfoliates  B.  B. 

Diff.  Differs  from  talc  and  chlorite  in  being  elastic,  the 
folia  tougher  and  harder;  yet  hydrous  varieties  sometimes 
have  a  greasy  feel,  and  little  or  no  elasticity. 

Obs.  A  constituent  of  granite,  gneiss,  and  mica  schist, 
but  not  as  commonly  so  as  biotite.  The  larger  crystalliza- 
tions occur  in  granite  veins,  intersecting  these  rocks.  Along 
a  belt  of  country  in  New  England  east  of  the  Connecti- 
cut, in  New  Hampshire,  Massachusetts,  and  Connecticut, 
and  to  the  southwest,  in  Maryland,  Virginia,  North  Carolina, 
South  Carolina,  Alabama,  and  Georgia,  large  granite  veins 
occur,  and  many  valuable  deposits  of  mica  have  been  opened. 
The  chief  mines  of  New  England  are  at  Alstead,  Graf  ton, 
and  Groton,  where  plates  two  to  three  feet  across  have  been 
obtained;  mines  occur  in  Virginia,  but  more  important  in 
North  Carolina,  in  Yancey,  Mitchell,  and  Macon,  and  other 
cos. ;  Dakota  affords  much  mica,  chiefly  from  Custer  and 
Pennington  cos.  in  the  Black  Hills.  Mines  have  been  opened 
aleo  in  Colorado,  New  Mexico,  etc. ;  in  Canada  (Ontario) 
in  N.  Burgess,  Villeneuve,  etc.  Mica  occurs  also  in  in- 
teresting forms  at  Paris,  Me.;  Chesterfield,  Barre,  Brim- 
field,  and  South  Royalston,  Mass.;  near  Middletown  and 
Branch ville,  Ct. ;  near  Greenwood  Furnace,  Warwick,  and 
Edenville,  Orange  Co.,  and  in  Jefferson  and  St.  Lawrence 
cos.,  N.  Y. ;  Newton  and  Franklin,  N.  J.;  near  German- 
town,  Pa.;  Jones's  Falls,  Md. 

Mica  was  formerly  used  in  Siberia  for  glass  in  windows, 
whence  it  has  been  called  Muscovy  glass.  It  is  in  common 
use  in  lanterns;  for  the  doors  of  stoves  and  furnaces  and 
for  other  purposes  which  demand  a  tough  transparent  sub- 
stance not  easily  affected  by  heat.  It  is  also  ground  for 
some  ornamental  purposes.  About  150,000  pounds  of  sheet 
mica  ($370,000)  was  the  product  in  the  United  States  for 
1884,  and  92,000  pounds  ($161,000),  for  1885. 

Lepidolite.     A  lithium-bearing  muscovite;  color  rose-red,  and  lilac 
to  white;  in  crystalline  plates  and  aggregations  of  scales.     It  contains 
19 


290  DESCRIPTION'S   OF   MINERALS. 

from  2  to  5  percent  of  lithia,  and  hence  B.B.  imparts  a  deep  crimson 
color  to  the  flame.  It  is  mostly  of  the  species  muscovite,  and  the  rest 
is  zinnwaldite.  The  formula,  LiKAl2O9F2Si3  =  Silica  49  18,  alumi- 
na 27'87,  lithia  4'09,  potash  12'81,  fluorine  9'84  =  103'79.  Rozena, 
Moravia;  Saxony;  the  Ural;  Sweden;  Cornwall;  Paris,  Hebron,  etc., 
Maine;  Chesterfield,  Mass. ;  Middletown,  Ct.  The  red  mica  of  Goshen 
is  not  lithium-bearing. 

Margarodite,  HygropMlite,  Damourite,  Sericite,  Sterlingite.  Names 
for  micas  related  to  muscovite,  but  containing  4  or  5  per  cent,  of 
water.  While  mica  becomes  hydrated  on  weathering,  much  mica 
was  hydrous  at  its  origin.  A  hydrous  mica  is  distinguished  by  its 
greasy  feel  and  little  elasticity.  The  compact  pseud omorphous  mate- 
rial called  Pinite  has  the  constitution  of  a  hydrous  mica. 

(Ellacherite.  Like  whitish  muscovite  in  its  elastic  laminse,  polariza- 
tion, and  other  characters;  «but  an  analysis  obtained  only  7 '6  p.  c.  of 
potash  (with  1'4  of  soda),  along  with  about  5  p.  c.  of  baryta,  and 
4'4  of  water.  Kemmat,  in  Pfitschthal. 

Paragonite.  Resembles  much  muscovite;  occurs  in  pearly  scales 
constituting  a  schistose  rock;  G.  =  2 '75 -2 '9;  formula  like  that  given 
under  muscovite;  an  analysis  afforded  Silica  46 '81,  alumina  40 '06,  mag- 
nesia 0'65,  lime  T26,  soda  6'40,  water  4*82  =  100.  Monte  Campione, 
in  the  region  of  St.  Gothard.  Pregraltite  and  Cossaite  are  the  same. 

Cryophyllite.  Like  a  green  muscovite  and  similar  in  optic-axial 
angle.  G.  =  2'909.  But  an  analysis  obtained,  besides  13*15  p.  c.  of 
potash,  4  of  lithia  and  8  of  iron  protoxide,  with  2'49  of  fluorine;  an- 
other 10'6  of  K2O,  0'8  of  Na2O,  4'9  of  Li2O,  and  about  7.1  of  fluorine. 
Owing  apparently  to  the  unusual  percentage  of  alkali  and  fluorine, 
it  is  remarkable  for  its  fusibility,  it  fusing  in  the  flame  of  a  candle;  to 
this  the  name,  from  the  Greek  kruos,  ice,  alludes.  The  granite  of 
Cape  Ann,  Mass. 

Zinnwaldite  is  similar  to  the  last  in  containing  iron  and  lithium 
without  magnesium,  but  the  amount  of  alkali  metal  is  proportionally 
less,  and  fusion  is  less  easy.  Zinnwald. 

Polylithionite  is  very  similar,  but  contains  59  p.  c.  SiO2.  Green- 
land. 

Phlogopite. 

Monoclinie.  Color  often  yellowish  brown  with  a  copper- 
like  reflection;  also  brownish  yellow  to  white.  Optic-axial 
angle  3°  to  20°. 

Composition.  Mostly  (JK8iAl)4036SiT,  in  which  (HK): 
Mg  =  1  to  5.  An  analysis  afforded"  Silica  43-00,  alumina 
12-37,  iron  sesquioxide  1*71,  magnesia  27*70,  potash  10-32, 
soda  0-30,  water  0-38,  fluorine  5*67  =  102-35.  B.B.  like 
muscovite,  but  reaction  for  more  fluorine. 

Obs.  From  the  crystalline  limestone  of  St.  Lawrence, 
Jefferson,  Essex,  and  Orange  cos.,  N.  Y.,  and  Sussex  Co., 
N.  J.;  Burgess,  Canada,  etc. 

Aspidolite  is  a  related  mica.       ; 


MICA    GROUP. 


Biotite. 

Monoclinic.  Crystals  usually  short,  erect,  rhombic  or 
hexagonal  prisms.  Twins  of  six  individuals  not  infrequent, 
as  optically  detected.  Common  in  disseminated  scales; 
also  in  masses  made  up  of  an  aggregation  of  scales. 

Color  dark  green  to  black,  rarely  white.  Transparent  to 
opaque.  Lustre  more  or  less  pearly  on  a  cleavage  surface. 
Optic-axial  angle  often  less  than  1°;  crystals  often  appar- 
ently uniaxial.  H.  =  2-5-3.  G.  =  2-7-3'L 

Composition.  Mostly  (f  R3f  R)2012Si3,  in  which  R  =  iron, 
magnesium,  potassium,  and  hydrogen  (of  water  present), 
and  R  —  aluminium.  In  one  analysis,  Silica  40-00,  alumina 
17*28,  iron  sesquioxide,  0'72,  iron  protoxide  4*88,  magnesia 
23-91,  potash  8'57,  soda  1-47,  water  1-37,  fluorine  1-57  = 
99-77.  B.B.  whitens  and  fuses  on  thin  edges;  sometimes  a 
red  flame  from  reaction  for  lithium.  This  species  has  been 
called  Anomite.  Euclilorite  is  biotite.  The  approach  to 
uniaxial  character  optically  in  this  mica  has  been  explained 
by  J.  P.  Cooke  on  the  view  of  a  twinning  between  succes- 
sive laminae,  making  an  overlapping  compound  structure. 

Obs.  Common  as  a  constituent  of  mica  schist,  gneiss,  and 
granite,  much  more  common  than  muscovite;  often  pres- 
ent in  syenyte;  occurs  in  black  scales  in  some  trachytes. 
While  differing  from  muscovite  in  the  presence  of  magne- 
sium and  iron,  the  percentage  of  potash  is  but  little  less 
(about  9  per  cent.).  Occurs  in  large  black,  greenish,  and 
brownish-black  crystallizations  at  Greenwood  Furnace,  Mon- 
roe, N.  Y.  ;  in  veins  in  granite  at  Middletown,  Portland,  and 
Stony  Creek,  Ct.,  a  kind  affording  lithia  reactions,  and 
oxidizing  easily;  Moriah,  Essex  Co.,  N.  Y.;  Topsham,  Me., 
crimson;  Easton,  Pa.;,  white. 

Meroxene.  The  so-called  biotite,  or  black  mica,  of  Vesuvius;  unlike 
biotite,  it  has  the  optic-axial  plane  parallel  (instead  of  at  right-angles 
to)  the  plane  of  symmetry. 

Lepidomelane.  Resembles  biotite,  but  thin  folia  are  but  little  elastic, 
or  are  brittle,  and  the  proportion  of  iron  oxide  is  larger  (20  to  30  p.  c.), 
with  less  magnesia  (3  to  7  p.  c.).  Wermland,  Sweden. 

BaugJltonvK.  Between  biotite  and  lepidomelane.  Contains  7  to  15 
p.  c.  of  magnesia.  Fuses  with  difficulty.  From  granite,  dioryte,  etc., 
of  Ireland. 

Annite.  Related  to  lepidomelane,  but  contains  almost  no  magnesia 
(O'GO  p.  c.).  From  Cape  Ann.  Another,  of  same  loc.,  contains  less 
silica  (32  p.  c.)  and  much  more  FeO  (30  '3).  Annite  crystals  have 
sometimes  a  border  of  cryophyllite. 


292 


DESCRIPTIONS   OF   MINERALS. 


SiderophyUiie.  Like  Annite  in  the  near  absence  of  magnesia  (1*14 
p.  c.);  B.B.  fuses  easily.  From  Pike's  Peak. 

Astrophyllite.  A  mica  of  doubtful  relations;  Las  been  referred  to  the 
pyroxene  group;  has  the  small  amount  of  silica  (33-35  p.  c  )  that  char- 
acterizes the  chlorite  group,  and  3'5-4'5  p.  c.  of  water;  contains  be- 
sides iron  protoxide,  7  to  14  p.  c.  of  titanium  dioxide  and  some  zirconia 
and  potash.  Norway;  El  Paso  Co.,  Col. 

SCAPOLITE  GROUP. 

The  Scapolite  species  are  tetragonal  in  crystallization, 
usually  white  in  color  or  of  some  light  shade,  and  analyses 
afford  alumina  and  lime  with  or  without  soda.  The  lime 
scapolites  are  unisilicate  in  ratio;  the  others,  containing 
alkali,  have,  with  one  exception,  more  silica  than  this  ratio 
requires. 

Wernerite. — Scapolite. 

Tetragonal;  1  A  1  =  136°  7'.  Cleavage  rather  indistinct 
parallel  with  i-i  and  /.  Also  massive, 
suhlamellar,  or  sometimes  faintly  fi- 
brous in  appearance. 

Colors  light;  white,  gray,  pale  blue, 
greenish  or  reddish;  brown  when  im- 
pure. Streak  uncolored.  Trans- 
parent to  nearly  opaque.  Lustre  usu- 
ally a  little  pearly.  H.  =  5-6.  G.  = 
2-65-2-8. 

Composition.  (£[Ca,:Naa]f  Al)2012Sis 

=  Silica  48-4,  alumina  28-5,  lime  18-1,  soda  5-0  =  100;  but 
contains  also  1  to  2*5  p.  c.  of  chlorine.  B.B.  fuses  easily 
with  intumescence  to  a  white  glass;  imperfectly  decomposed 
by  hydrochloric  acid. 

Diff.  The  square  prisms  and  the  angle  of  the  pyramid  at 
.summit  are  characteristic.  In  cleavable  masses  it  resembles 
a  feldspar,  except  for  a  slight  fibrous  appearance  usually  dis- 
tinguished on  the  cleavage  surface.  More  fusible  than 
feldspar,  and  of  higher  specific  gravity.  Spodumene  has  a 
much  higher  specific  gravity,  and  differs  also  B.B.  Wollas- 
tonite  is  more  fibrous  in  the  appearance  of  the  surface,  is 
less  hard,  and  gelatinizes  with  acids. 

Obs.  Found  mostly  in  the  older  crystalline  rocks,  and 
also  in  some  volcanic  rocks;  especially  common  in  granular 
limestone.  Crystals  occur  at  Gouverneur,  Two  Ponds, 
Amity,  K.  Y.;  Bolton,  Boxborough,  Littleton,  Mass.; 


SCAPOLITE   GROUP.  293 

Franklin,  Newton,  N.  J. ;  massive  at  Marlboro',  Vt. ;  West- 
field,  Mass. ;  Monroe,  Tyringham,  Ct.  Foreign  localities  are 
at  Arendal,  Norway;  Wermland,  Sweden;  Pargas  in  Finland. 

Chelmsfordite,  Nuttallite^  Ontoriolite,  Glaucolite,  are  varieties  of  this 
species.  Paranthine  and  Elcebergite  are  similar,  being  distinguishable 
from  it  only  by  chemical  analysis. 

Sarcolite.  Tetragonal  and  like  wernerite;  reddish  white  to  rose-red; 
H.  =  6;  G.  =  2-9-2-95;  formula  (iCa3iAl)2Oi2Si3;  gelatinizes  with 
acids.  In  small  geodes,  Mt.  Somma. 

Meionite.  A  lime  scapolite,  like  wernerite  in  crystals,  but  having 
the  formula  (iCa|;Al)2Oi2Si3,  being  a  true  unisilicate.  Monte  Somma. 

Dipyre  is  near  wernerite,  but  contains  more  silica  (56  p.  c.)  and  10 
per  cent,  of  soda.  The  Pyrenees. 

Mizzonite  and  Marialite  are  other  kinds  containing  much  soda  and 
silica,  the  latter  60  p.  c. 

Nephelite.— Nepheline. 

Hexagonal.  In  hexagonal  prisms  with  replaced  basal 
edges;  0  A  1  =  135°  55'.  '  Also  massive;  rarely  thin  colum- 
nar. 

Color  white,  or  gray,  yellowish,  greenish,  bluish  red. 
Lustre  vitreous  to  greasy.  Transparent  to  opaque.  H.  = 
5-5-6.  G.  =2-55-2-62. 

Composition.  (Na2,  K2)4Al4034Si?,  the  oxygen  ratio  being 
1  :  3  :  4J.  An  analysis  afforded  Silica  44 '0,  alumina  33*3, 
Fe03,  Mn03  0-7,  lime  1-8,  soda  15-4,  potash  4-9,  water  0'2 
=  100  -3 ;  a  little  lime  is  usually  present.  B.  B.  fuses  quietly 
to  a  colorless  glass.  Decomposed  by  hydrochloric  acid,  and 
the  solution  gelatinizes  easily  on  evaporation. 

Named  from  the  Greek  nephele,  cloud,  the  mineral  becom- 
ing clouded  in  acid.  Includes  the  glassy  crystals  from  Ve- 
suvius called  Sommile;  also  hexagonal  crystals  in  other 
volcanic  rocks;  a  massive  variety,  of  greasy  lustre,  called 
Elceolite  from  the  Greek  elaion,  oil.  Altered  crystals  are 
in  part  the  mineral  Gieseckite. 

biff.  Distinguished  from  most  scapolites  and  feldspars 
by  the  greasy  lustre  when  massive,  and  the  facility  with 
which  it  gelatinizes  with  acids;  from  apatite  by  the  last 
character,  and  also  its  greater  hardness. 

Obs.  The  prominent  constituent  of  nephelindoleryte  or 
nephelinyte,  and  phonolyte,  and  also  in  some  other  eruptive 
rocks;  enters  into  the  constitution  of  miascyte,  zircon- 
syenyte,  and  some  metamorphic  rocks.  Among  the  localities 
are  Vesuvius  and  C.  di  Bove,  in  Italy;  Katzenbuckel,  near 


294 


DESCRIPTIONS   OF   MINERALS. 


Heidelberg;  Aussig,  in  Bohemia;  and  as  elaeolite,  Brevig, 
Norway;  Siberia;  the  Ozark  Mountains,  Arkansas;  Litch- 
field, Maine. 

Cancrinite.  Like  nephelite  in  crystallization,  also  in  composition, 
except  the  presence  of  some  carbonates  and  usually  water;  color  white, 
gray,  yellow,  green,  blue,  or  reddish;  H.  — •  5-6;  G.  =  2 '4-2*5;  on 
account  of  the  carbonates  it  effervesces  in  acids.  B.B.  fuses  very 
easily. 

Occurs  in  crystalline  rocks  at  Miask  in  the  Ural;  in  Norway;  Tran- 
sylvania; and  at  Litchfield  in  Maine,  with  elaeolite  and  sodalite. 
Microsommite.     Near  neph elite  in  form;  also  in  composition,  except 
the  presence  of  much  chlorine  (6  '2  to  8  p. 
c.)  and  sulphuric  acid  (4  to  5*26  p.  c.);  col- 
orless to  yellow.     In  large  crystals  from 
Mt.  Somma;  and  in  small  from  bombs 
ejected  by  Vesuvius  in  1872.    Davyne  is 
in  part  altered  microsOmmite. 

Eucryptite.  Hexagonal.  Crystallized 
microscopically  within  albite,  in  forms 
like  those  of  the  quartz  of  graphic  granite, 
as  in  the  figure.  Composition  Li2AlO&Si2, 
near  that  of  nephelite.  Both  the  albite 
and  eucryptite  a  result  of  the  alteration  of 
spodumene,  at  Branchyille,  Ct.;  and  shown  by  Brush  and  E.  8. 
Dana  to  be  an  intermediate  stage  in  the  change  from  spodumene  to 
muscovite.  Gelatinizes  in  acid. 


Sodalite. 

Isometric.  In  dodecahedrons  ;  cleavage  dodecahedral. 
Color  brown,  gray,  or  blue.  Lustre  vitreous,  sometimes 
greasy.  H.  =6.  G.  =  2  '25-2  -4. 

Composition.  Na2A10bSi2  -f  £NaCl  =  Silica  37 •!,  alumina 
31-7,  soda  19-2,  sodium  4%  chlorine  7 '3  =  100.  B.B. 
fuses  with  intumescence  to  a  colorless  glass.  Decomposed 
by  hydrochloric  acid,  and  the  solution  gelatinizes  on  evapo- 
ration. 

Occurs  in  eruptive  and  metamorphic  rocks.  Found  in 
Sicily;  near  Lake  Laach;  at  Miask;  in  Norway;  W.  Green- 
land; Bolivia;  blue,  at  Litchfield,  Me.;  lavender-blue  at 
Salem,  Mass. 

Hauynite  (or  Hauyne).  Near  sodalite  in  form  and  composition; 
blue  to  greenish;  contains  about  12  p.  c.  of  sulphuric  acid.  From 
lavas  of  Mt.  Somma;  L.  Laach;  Mt.  Dor,  etc.  Nosite  (or  noscan)  is 
similar.  Ittnerite  and  Skolopsite  are  altered  hailynite  or  nosite. 


SC  A  POLITE   GKOUP.  295 

Lapis-Lazuli.  —Ultramarine. 

Isometric;  rarely  in  crystals  (dodecahedrons);  cleavage 
imperfect.  Usually  massive.  Color  rich  Berlin  or  azure 
blue.  Lustre  vitreous.  Translucent  to  opaque.  H.  =  5*5. 
G.  =2-3-2-5. 

Composition.  Silica  45*5,  alumina  31'8,  soda  9*1,  lime 
3'5,  iron  0'8,  sulphuric  acid  5*9,  sulphur  0*9,  chlorine  0'4, 
water  O'l  =  98*0.  B.B.  fuses  to  a  white  translucent  or 
opaque  glass,  and  if  calcined  and  reduced  to  powder,  loses 
its  color  in  acids.  Color  supposed  to  be  due  to  sodium 
sulphide.  The  mineral  is  not  homogeneous,  but  the  exact 
nature  of  the  ultramarine  species  at  the  basis  of  it  is  not  yet 
ascertained. 

Obs.  Found  in  syenyte  and  granular  limestone.  Brought 
from  Persia,  China,  Siberia,  and  Bucharia.  The  specimens 
often  contain  scales  of  mica  and  disseminated  pyrites. 

The  richly-colored  lapis-lazuli  is  highly  esteemed  for 
costly  vases,  and  for  inlaid  work,  and  is  used  also  in  the 
manufacture  of  mosaics.  It  is  the  material  of  the  beautiful 
and  durable  blue  paint  called  Ultramarine,  which  has  been 
a  costly  color.  An  artificial  ultramarine  is  made  which 
is  equal  to  the  native,  and  comparatively  cheap;  it  con- 
sists of  silica  45*6,  alumina  23  -3,  soda  21  -5,  potash  !•?, 
lime  trace,  sulphuric  acid  3*8,  sulphur  1'7,  iron  1*1,  and 
chlorine  a  small  quantity  undetermined. 

Leucite. — Amphigene. 

Isometric.     Form  the  trapezohedron,  as  in  the  figure. 
Cleavage  imperfect.     Usually  in  dull  glassy 
white  to  gray  crystals,  disseminated  through 
lava.     Translucent  to  opaque.     H.  —  5  '5-6. 
G.  =2-45-2-5.     Brittle. 

Composition.  KQA1012Si4  =  Silica  55-0, 
alumina  23-5,  potash  21 -5  =  100.  B.B.  in- 
fusible. Moistened  with  cobalt  nitrate  and 
ignited  assumes  a  blue  color.  Decomposed 
by  hydrochloric  acid,  without  gelatinizing. 

Diff.  Distinguished  from  analcite  by  its  hardness  and  in- 
fusibility. 

Obs.  In  volcanic  rocks,  and  abundant  in  those  of  Italy, 
especially  at  Vesuvius,  where  some  crystals  are  an  inch  in 
diameter.  Also  found  in  the  Leucite  Hills,  northwest  of 


296  DESCRIPTIONS   OF   MINERALS. 

Point  of  Rocks,  "Wyoming  Territory;  in  Cerro  de  los  Vir- 
gines,  Cal. 

Named  from  the  Greek  leukos,  white.  The  crystals  give 
usually  the  angles  of  a  tetragonal  form,  but  this  is  believed 
to  be  an  irregularity  due  to  the  internal  condition  of  the 
crystal  (p.  79). 

FELDSPAR  GROUP. 

The  species  of  the  Feldspar  Group  are  related — 

A.  In  crystallization:  (1)  the  forms  being  all  oblique; 
(2)  the  angle  of  the  fundamental  rhombic  prism  7,  in  each, 
nearly  120°;  (3)  the  other  angles  differing  but  little,  al- 
though part  of  the  species  are  monoclinic  and  part  tri- 
clinic;  and  (4)  there  being  two  directions  of  easy  cleavage, 
one,  the  most  perfect,  parallel  to  the  basal  plane  0,  and  the 
other  parallel  to  the  shorter  diagonal  section,  with  the  in- 
tervening angle,  "  the  cleavage  angle, "  either  90°  (as  in  the 
mo-noclinic  species  orthoclase  and  hyalophane),  or  nearly 
90°  (as  in  the  triclinic  species).     The  triclinic  feldspars  are 
often  called  by  the  general  name  Plagiodase. 

B.  In  composition :  (1)  the  only  element  in  the  sesquiox- 
ide  state  being  aluminium,  and  those  in  the  protoxide  state 
potassium,  sodium,  or  calcium,  or  two  or  three  of  these 
bases  together,  rarely  with  barium;  (2)  the  constant  ratio 
of  1  atom  of  R  to  1  of  R;  (3)  the  amount  of  silica  in  the 
species  increasing  with  the  proportion  of  alkali,  being  that 
of  a  unisilicate  in  the  pure  lime-feldspar,  anorthite;  that 
of  a  tersilicate  in  the  soda-feldspar,  albite,  or  potash-feld- 
spar, orthoclase;  and  so  directly  proportioned  to  the  alkali, 
that  the   amount   in   any  lime-and-soda  feldspar  may  be 
deduced  by  taking  the  lime  (or  calcium)  as  existing  in  the 
state  of  a  unisilicate,  and  the  soda  in  that  of  a  tersilicate, 
and  adding  the  two  together. 

Anorthite  has  the  formula  CaA108Si2. 

Albite  "  "        Na2A1016Si6. 

The  constitution  of  a  species  containing  Ca  and  Na2  in 
the  ratio  of  1  to  1  for  the  protoxide  portion  may  be  ob- 
.tained  as  follows.  Adding  together  the  anorthite  and  albite 
formulas,  we  have  CaNa2Al2024SiR;  then  dividing  by  2,  the 
formulas  become  -|Ca^Na2A10128i4,  which  expresses  the 
composition  of  andesite.  With  3  parts  of  the  Ca  unisili- 
cate, and  1  of  the  Naa  tersilicate,  the  composition  is  that 


FELDSPAR  GROUP.  297 

of  labradorite.  So  it  is  for  other  combinations,  that  is  for 
other  species  between  anbrthite  and  albite  in  composition  ; 
and  since  still  other  intermediate  kinds  exist,  it  is  supposed 
that  all  the  varieties  between  the  two  above-mentioned 
species  are  isomorphous  combinations  of  them. 

The  quantivalent  or  oxygen  ratio  for  the  R,  Al,  Si,  in  the 
several  species  of  the  group,  is  as  follows:  V  means  triclinic 
in  crystallization,  and  IV  monoclinic;  and  K,  Na,  Ca,  Ba, 
the  protoxide  basic  element  of  the  species. 

SYSTEM    OF  SYSTEM  OP 

RATIO.   CRYSTALLI-  RATIO.    CRYSTAL- 

ZATION.  LIZATION. 

Anorthite,  Ca,             1:3:4  V,  Oliproclase,  Na,  Ca,  1 :  3  :  9  V. 

Labradorite,  Ca,  Na,  1  :  3  :  6  V,  Albite,  Na,                 1  :  3  :  12  V. 

Hyalophane,  Ba,         1:3:8  IV,  Microcline,  K,           1  : 3 :  12  V. 

Andesite,  Na,  Ca,       1:3:8  V,  Orthoclase,  K,          1  : 3 :  12  IV. 

These  are  the  normal  ratios;  but  there  is  variation  from 
them  in  the  analyses,  part^of  which  is  variation  in  actual 
composition,  and  part  a  result  of  interlamination  or  mixture 
of'two  feldspars.'  Thus,  orthoclase  occurs  mixed  with 
micro-dine,  albite,  or  oligoclase.  But  while  such  mixtures 
account  for  the  soda  found  in  some  analyses  of  orthoclase, 
it  does  not  for  that  in  all,  since  soda  does  occur  in  many 
specimens  of  pure  orthoclase,  replacing  part  of  the  potash. 
It  is  the  same  with  the  triclinic  feldspar  microcline,  which 
has  the  composition  of  orthoclase,  and  may  have  'the  alkali 
portion  all  potash  or  part  soda,  one  analysis  of  typical 
microcline  giving  only  0*48  of  soda.  It  is,  hence,  not  safe 
to  calculate  the  percentage  of  orthoclase  present  in  a  feld- 
spar, or  in  a  mixture,  from  the  percentage  of  potash.  More- 
over, potash  is  present  in  much  albite. 

The  above  ratios  show  that  anorthite  has  for  the  oxygen 
ratio  between  R  -\-  R  and  Si,  4  :  4,  or  1  :  1,  as  in  true  uni- 
silicates;  while  in  albite  and  orthoclase,  the  same  ratio  is 
4  :  12  or  1  :  3,  that  of  a  tersilicate,  as  above  stated. 

C.  In  physical  characters :  hardness  between  6  and  7 ; 
specific  gravity,  between  2-44  and  2*75  ;  lustre  vitreous, 
but  often  pearly  on  the  face  of  perfect  cleavage  ;  and  each 
species  transparent  to  subtranslucent. 

Distinctive  characters.  The  form  is  sufficient  to  deter- 
mine a  feldspar  when  it  is  in  defined  crystals;  so  also  the 
fact  of  two  unequal  cleavages  inclined  to  one  another  at 
84°  to  90°,  one  of  them  quite  perfect.  No  fibrous,  colum- 
nar, or  micaceous  varieties  are  known.  They  differ  from 


298  DESCRIPTIONS   OF   MINERALS. 

rhodonite,  by  the  absence  of  a  manganese  reaction  ;  from 
spodumene,  by  the  absence  of  a  lithia  reaction  as  well  as 
cleavage  angle;  from  scapolite,  by  form;  from  nephelite,  by 
form,  and  also  more  difficult  fusibility,  and  by  not  gelatiniz- 
ing with  acids,  except  in  the  case  of  anorthite,  which  gela- 
tinizes readily.  For  optical  characters  see  page  78,  and 
beyond,  under  Petrology. 

Anorthite. — Indianite.    Lime  Feldspar. 

Triclinic;  cleavage  angle  85°  50'  and  94°  10'.  Crystals 
tabular.  Also  massive  granular  or  coarse  lamellar.  Color 
white,  grayish,  reddish.  G.  =  2  -66-2  '78. 

Composition.  CaA108Si2  =  Silica  43*1,  alumina  36*8, 
lime  20-1  =  100.  B.B.  fuses  with  much  difficulty  to  a 
colorless  glass;  decomposed  by  hydrochloric  acid,  and  the 
solution  gelatinizes  on  evaporation. 

Obs.  Occurs  in  basic  eruptive  rocks;  also  in  some  meta- 
morphic  rocks.  Found  in  the  lava  of  Vesuvius;  the  Tyrol; 
Faroe  Islands,  Iceland;  in  imbedded  crystals  in  some  doler- 
yte  of  the  Connecticut  Valley;  in  altered  crystals  (saussur- 
ite)  at  Hanover,  N.  H. ;  in  diabase  and  gabbro  of  Keweenaw 
Point;  as  a  rock  with  large  crystals  on  the  north  or  Min- 
nesota shore  of  L.  Superior.  Barsowite  is  referred  here. 

Bytownile.  Near  anorthite,  but  having  more  silica  (46-48  p.  c.),  with 
some  soda,  and  the  oxygen  ratio  1:3:5.  The  Minnesota  anorthite 
gives  the  unusual  ratio  1  :  2'4  :  4 "15. 

Labradorite.— Lime-soda  Feldspar.     Labrador  Feldspar. 

Triclinic;  cleavage  angle  93°  20'  and  86°  40'.  Usually 
in  cleavable  massive  forms. 

Color  dark  gray,  brown,  or  greenish  brown;  also  white  or 
colorless.  Often  a  series  of  bright  chatoyant  colors  from 
internal  reflections,  especially  blue  and  green,  with  more  or 
less  of  yellow,  red,  and  pearl-gray.  G.  =  2'67-2*70. 

Composition.  fCaiNa2A1010Si3  =  Silica  52 -9,  alumina 
30-3,  lime  12-3,  soda  4-5  =  100.  Sometimes  a  little  potash 
in  place  of  the  soda.  B.B.  fuses  easily  to  a  colorless  glass. 
Only  partially  decomposed  by  hydrochloric  acid. 

Obs.  A  constituent  of  the  larger  part  of  basic  eruptive 
rocks  and  lavas;  and  also  of  some  metamorphic  rocks.  An 
ingredient  in  part  of  the  Archaean  rocks.  Named  from  its 
first  discovery  in  Labrador. 


FELDSPAR   GROUP.  299 

Andesite.  Triclinic;  cleavage  angle  87°-88°.  -  Near  labradorite  in 
composition;  the  formula  4CaANaaAlO12Si4  =  Silica  59 '8,  alumina 
25'5,  lime  7'0,  soda  7 '7  =  100 '0. 

Hyalophane.  Monoclinic,  and,  hence,  the  cleavage  angle  90°.  A 
baryta  feldspar;  the  formula  like  that  of  andesite,  excepting  the  sub- 
stitution of  Ba  for  Ca  and  K2  for  Naa.  G.  =  2'8-2'9.  Binnenthal, 
Switzerland;  Jakobsberg,  Sweden. 

A  triclinic  baryta-feldspar,  having  the  ratio  of  andesite,  1:3:8, 
and  the  cleavage  angle  86°  37'  with  G.  =  2 '835,  has  been  described ; 
it  approaches  oligoclase  in  optical  characters. 

Oligoclase.— Soda-lime  Feldspar. 

Triclinic;  cleavage  angle  93°  50'  and  86°  10'.  Commonly 
in  cleavable  masses.  Also  massive. 

Color  usually  white,  grayish  white,  grayish  green,  green- 
ish, reddish.  Transparent,  subtranslucent.  H.  =  6-7. 
G.  =2-5-2-7. 

Composition.  iCa|Na2A1014Si5  =  Silica  61*9,  alumina 
24-1,  lime  5'2,  soda  8-8  =  100.  A  portion  of  the  soda  is 
usually  replaced  by  potash.  B.B.  fuses  without  difficulty; 
not  decomposed  by  acids. 

Obs.  Occurs  in  granite,  gneiss,  syenyte,  and  various 
metamorphic  rocks,  especially  those  containing  much  silica; 
and  in  such  case  usually  associated  with  orthoclase.  Sun- 
stone  is  in  part  oligoclase,  giving  bright  reflection  from  the 
interior,  owing  to  disseminated  scales  of  hematite.  Occurs 
in  Norway.  Moonstone  is  in  part  a  whitish  opalescent 
variety.  Oligoclase  occurs  at  Union ville,  Blue  Hill,  Pa.; 
Haddam,  Conn. ;  Mineral  Hill,  Del. ;  Chester,  Mass.,  etc. ; 
the  Urals;  Finland;  Norway;  Bohemia;  Elba. 

Albite.— Soda  Feldspar. 

Triclinic.  Cleavage  angle  93°  36',  and  86°  24'.  Figures 
1  to  6  represent  some  of  its  forms;  2  and  3  are  twin 
crystals.  Crystals  usually  more  or  less  thick  tabular.  Also 
massive,  with  a  granular  or  lamellar  structure.  Color 
white;  occasionally  light  tints  of  bluish  white,  grayish, 
reddish,  and  greenish^  Transparent  to  subtranslucent. 
H.  =6-7.  G.  =  2-61-2-62. 

Composition.  Na2A1016Si6  =  Silica  68-6,  alumina  19-6, 
soda  11  *8  =  100  -0.  „  B.  B.  fuses  to  a  colorless  or  white  glass, 
imparting  an  intense  yellow  to  the  flame.  Not  acted  upon 
by  acids. 


300 


DESCRIPTIONS   OF   MINERALS. 


Cleavelandite  is 'a  lamellar  variety  occurring  in  wedge- 
shaped  masses  at  the  Chesterfield  albite  vein,  Mass. 


Ols.  Albite  occurs  in  some  granites  and  gneiss,  and  is 
most  abundant  in  granite  veins.  Fine  crystals  occur  at 
Middletown,  Haddam,and  Branch  ville,  Ct.;  Goshen,  Mass.; 
Granville,  N".  Y.;  TJnionville,  Delaware  County,  Pa. 

Named  from  the  Latin  albus,  white. 

Microcline. — Potash  Feldspar. 

Triclinic;  cleavage  angle  within  16'  of  90°.  In  angles, 
and  also  in  physical  characters,  nearly  identical  with  ortho- 
clase,  but  the  cleavage  surface  shows  sometimes  the  fine 
striations  due  to  twinning.  When  viewed  with  polarized 
light,  the  twinned  structure  is  distinct,  but  differs  from  other 
triclinic  feldspars  in  a  blocked  arrangement,  owing  to  a 
transverse  twinning  (Fig.  13,  p.  79).  Colors  white,  flesh- 
red,  copper-green.  The  green  variety  has  been  called 
Amazon-stone  ;  the  color  comes,  according  to  Konig,  from 
the  presence  of  an  organic  salt  of  iron. 

Occurs  in  the  zircon-syenyte  of  Norway;  also  in  the 
Urals;  Greenland;  Labrador;  Leverett,  Mass.;  Branch ville, 
Ct.;  Delaware;  Chester  Co.,  Pa.  (Chestertiie);  White  Moun- 
tain Notch;  Pike's  Peak  (Amazon-stone);  Magnet  Cove,  Ark. 

Orthoclase. — Common  Feldspar.    Potash  Feldspar. 

Monoclinic ;  the  cleavage  -  angle  90°.  Figures  1  to  3 
represent  common  forms,  and  4  to  8,  twins ;  4,  twinned 


FELDSPAR   GEOUP. 


301 


parallel  to  0;  5,  6,  parallel  to  i-l,  Carlsbad  twins;  7,  par- 
allel to  24,  Baveno  twin;  8,  same  as  7,  but  made  up  of  four 
crystals  instead  of  two.  Usually  in  thick  prisms,  often 


3. 


rectangular,  and  also  in  modified  tables.  Also  massive,  with 
a  granular  structure,  or  coarse  lamellar  ;  also  fine-grained, 
massive,  crypto-crystalline.  Colors  light;  white,  gray,  and 
flesh-red  common;  also  greenish  and  bluish  white  and  green. 
H.  =  6.  G.  =  2-55-2*58. 

Composition.  KaA1016Si6  =  Silica  64-7,  alumina  18*4, 
potash  16 -9  =  100.  Soda  sometimes  replaces  a  portion  of 
the  potash.  B.B.  fuses  with  difficulty;  not  acted  on  by 
acids. 

Common  feldspar  is  the  common  subtranslucent  variety; 
Adularia,  the  white  or  colorless  subtransparent,  the  name 
derived  from  Adula,  one  of  the  highest  peaks  of  St.  Gothard; 
Sanidin  or  glassy  feldspar,  transparent  tabular  crystals, 
often  occurring  in  trachytes  and  lavas ;  but  some  of  the 
"glassy  feldspar"  belongs  to  the  species  oligoclase  or  anor- 
thite;  Loxodase,  a  grayish  variety,  with  a  pearly  or  greasy 
lustre,  that  contains  much  soda. 

Moonstone  is  an  opalescent  variety  of  adularia,  haying 
when  polished  peculiar  pearly  reflections.  Sunstone  is  simi- 
lar; but  contains  minute  scales  of  mica.  A venturine  feld- 
spar often  owes  its  iridescence  to  minute  crystals  of  hema- 
tite, ilmenite,  or  gothite.  Sunstone  and  moonstone  are 
mostly  oligoclase,  and  so  is  a  large  part  of  aventurine  feld- 
spar. 


302  DESCRIPTIONS   OF   MINERALS. 

Diff.  Distinguished  from  the  other  feldspars  by  its  right- 
angled  cleavage  and  the  absence  of  striated  surfaces. 

Obs.  One  of  the  constituents  of  granite,  syenyte,  gneiss, 
and  other  related  rocks;  also  of  porphyry,  and  trachyte; 
and  it  often  occurs  in  these  rocks  in  imbedded  crystals. 
St.  Lawrence  Co.,  N.  Y.,  affords  fine  crystals;  also  Orange 
Co.,  N.  Y.;  Haddam  and  Middletown,  Conn.;  Acworth, 
N.  H. ;  South  Royalston  and  Barre,  Mass.,  etc.;  Lenni,  Pa. 
(Lennilite  and  Delawarite).  Green  feldspar  occurs  at 
Mount  Desert,  Me. ;  an  aventurine  feldspar  at  Leiperville, 
Penn. ;  adularia  at  Haddam  and  Norwich,  Conn.,  and  Par- 
sonsfield,  Me.  A  fetid  feldspar  (sometimes  called  Necronite) 
is  found  at  Roger's  Rock,  Essex  Co.,  N.  Y.;  21  miles  from 
Baltimore,  Md.  Carlsbad  and  Elbogen  in  Bohemia;  Baveno 
in  Piedmont;  St.  Gothard;  Arendal  in  Norway;  Land's  End; 
the  Mourne  Mountains,  Ireland;  are  some  of  the  more  in- 
teresting foreign  localities.  Cassinite,  from  near  Media, 
Pa.,  contains  much  intercalated  albite. 

Fehite  is  compact,  uncleavable  orthoclase,  having  the 
texture  of  jasper  or  flint,  which  it  much  resembles.  It 
generally  contains  disseminated  silica.  Colors  various,  as 
white,  gray,  brown,  red,  brownish  red  and  black;  sometimes 
banded.  It  is  distinguished  from  flint  or  jasper  by  its 
fusibility.  It  is  the  material  of  beds  or  strata  in  some 
rock  formations,  and  also  of  dikes  or  masses  of  eruptive 
rocks.  It  is  the  base  of  much  red  porphyry.  The  vicinity 
of  Marblehead,  Mass.,  is  one  of  its  localities. 

The  name  feldspar  is  from  the  German  word  Feld,  mean- 
ing field.  It  is,  therefore,  wrong  to  write  it  felspar, 

Orthoclase  is  used  extensively  in  the  manufacture  of  por- 
celain. The  large  granite  veins  of  Middletown,  Portland, 
and  Branch ville,  Conn.,  are  quarried  in  several  places  for 
this  purpose. 

Kaolin.  This  name  is  applied  to  the  clay  that  results 
from  the  decomposition  of  feldspar.  See  Kaolimte,  p.  332. 

Soda-orthoclase.  A  monoclinic  soda-feldspar  from.  Pantellaria ; 
differing  from  typical  orthoclase  in  having  two  thirds  aiomically  of 
the  potassium  replaced  by  sodium. 

III.  SUBSILICATES. 

In  the  Subsilicates,  as  stated  on  page  262,  the  combin- 
ing or  quantivalent  ratio  between  the  bases  and  silica  is  1 


SUBSILICATES.  303 

to  less  than  1.  In  Chondrodite,  the  first  of  the  following 
species,  the  ratio  is  4  :  3;  in  Tourmaline,  Andalusite,  Cya- 
nite, and  Fibrolite,  3  :  2.  Analyses  of  Andalusite  obtain  1 
of  alumina,  A103,  to  1  of  silica,  Si02,  giving  the  oxygen 
ratio  for  bases  and  silica  3  :  2,  which  is  the  composition 
also  of  cyanite  and  fibrolite ;  the  three  species,  andalusite, 
cyanite,  and  fibrolite  are  the  same  in  constituents  and 
atomic  ratio,  while  differing  in  crystalline  form,,  exemplify- 
ing a  case  of  trinwrphism  among  minerals. 

The  ratio  3  :  2  exists  also  in  Topaz,  Euclase  and  Da- 
tolite,  in  Titanite  or  sphene,  and  in  Keilhauite.  In  Stau- 
rolite,  the  ratio  is  2  :  1.  In  datolite  and  tourmaline  the 
basic  constituents  include  boron;  in  titanite  and  keilhauite, 
titanium;  in  datolite,  euclase,  and  part  of  staurolite,  hy- 
drogen, that  is,  the  hydrogen  of  the  water  found  on  analy- 
sis. In  chondrodite,  topaz,  and  some  tourmaline,  fluorine 
replaces  part  of  the  oxygen. 

Chondrodite. — Humite  in  part  (Scacchi's  Type  II.). 

Monoclinic.  Cleavage  indistinct.  Usually  in  imbedded 
grains-  or  masses.  Color  light  yellow  to  brownish  yellow, 
yellowish  red,  and  garnet-red.  Lustre  vitreous,  inclining 
a  little  to  resinous.  Streak  white,  or  slightly  yellowish  or 
grayish.  Translucent  to  subtranslucent.  Fracture  uneven. 
H.  =  6-6-5.  G.  =3-1-3-25. 

Composition.  Mg8014Sia  (=  8MgO  +  3Si02);  but  a  por- 
tion of  the  magnesium  replaced  by  iron,  and  a  part  of  the 
oxygen  by  fluorine.  A  specimen  from  firewater's,  New 
York,  afforded  Silica  34*1,  magnesia  53  °7,  iron  protoxide 
7 '3,  fluorine  4-1,  with  0'5  of  alumina  =  99- 7. 

B.B.  infusible.  Decomposed  by  hydrochloric  acid;  solu- 
tion gelatinizes  on  evaporation.  Reacts  for  fluorine. 

Diff.  Unlike  tdurmaline  or  garnet,  some  brownish-yel- 
low varieties  of  which  it  approaches  in  appearance,  it  does 
not  fuse,  and  reacts  for  fluorine.  Named  from  the  Greek 
chondros,  a  grain. 

Obs.  Abundant  in  Sussex  Co.,  N.  J.,  and  Orange  Co., 
N.  Y.,  occurring  at  Sparta  and  Bryam,  N.  J.,  and  in  War- 
wick and  other  places  in  N.  Y. ;  at  the  Tilly  Foster  Iron 
Mine,  Brewster's,  Putnam  County,  N.  Y.,  it  is  very  abund- 
ant; found  also  west  of  Kent,  and  in  Norfolk,  Ct. ;  East  Lee, 
Tyringham,  and  Hinsdale,  Mass.  At  Vesuvius  it  occurs 
in  small  crystals. 


304 


DESCRIPTIONS   OF   MINERALS. 


The  species  was  early  named  Chondrodtte,  from  Finland 
specimens.  Afterward,  small  crystals,  found  in  the  lavas 
of  Somma  (Vesuvius)  were  named  Humite,  and  both  were 
later  referred  to  the  same  species.  Now  three  species  of 
different  angles  and  form,  but  related  composition  and 
physical  character,  are  recognized  —  the  above  and  the  fol- 
lowing: 

Humite.  Orthorhombic  ;  embraces  part  of  Humite 
(Scacchi's  Type  I.),  and  some  large  crystals  found  at  Brews- 
ter's,  N.  Y.,  and  others  of  Sweden. 

CUnoJmmite.  Monoclinic;  includes  Scacchr's  Type  III. 
of  Humite,  and  some  of  the  crystals  from  Brewster's. 

Tourmaline. 

Ehombohedral;  R/\R  =  103°,  ~J  A  ~i  =  133°  8'.  Usual 
in  prisms  of  3,  6,  9,  or  12  sides,  terminating  in  a  low  3-sided 
pyramid;  sides  of  the  prisms  often  rounded  and  striated. 


2. 


3. 


Crystals  often  having  unlike  planes  at  the  two  extremities, 
as  shown  in  figure  3.  Also  compact  massive,  and  coarse 
columnar,  radiating  or  divergent  from  a  centre. 

Color  black,  blue-black,  and  dark  brown,  common  ;  also 
ruby-red,  pale  red,  rich  grass-green,  cinnamon-brown,  yel- 
low, gray,  and  colorless.  Sometimes  red  within  and  green 
externally,  or  one  color  at  one  extremity  and  another  at  the 
other.  Transparent ;  usually  translucent  to  nearly  opaque. 
Dichroic.  Lustre  vitreous,  inclining  to  resinous  on  a  sur- 
face of  fracture.  Streak  uncolored.  Brittle;  the  crystals 
often  fractured  across  and  breaking  very  easily.  H.  =  7  *0- 
7-5.  G.  =2-89-3-3. 

Composition.  (Ra,  B2,  R,)  05Si2,  in  which  R  includes,  in 
different  varieties,  Fe,  Mg,  Na2,  with  often  traces  also  of 
pa,  Mn,  K2,  Li2;  B  includes  aluminium,  with  some  boron 
in  the  trioxide  state  replacing  Al;  and  a  little  of  the  oxygen 
is  sometimes  replaced  by  fluorine. 


SUBSIL1CATES.  305 

Black,,  from  Haddam,  afforded  on  analysis,  Silica  37*50, 
boron  trioxide  (by  loss)  9 '02,  alumina  30-87,  iron  protoxide 
8-54,  magnesia  8'60,  lime  1-33,  soda  1'60,  potash  0*73, 
water  1 '81  =100.  A  red  from  Paris,  Maine,  afforded 
Fluorine  119,  silica  41-16,  boron  trioxide  (by  loss)  8*93, 
alumina  41*83,  manganese  protoxide  0*95,  magnesia  0'61, 
soda  1-3.7,  potash  2'17,  lithia  0*41,  water  2- -57  =  100. 

Varies  in  color  with  the  composition;  the  dark  contain 
much  iron  and  the  light  colors  but  little.  Rubellite  is  red; 
Indicolite  (from  Indigo)  blue  and  bluish  black;  Achroite, 
colorless.  Schorl  formerly  included  the  common  black 
tourmaline,  but  the  name  is  not  now  used. 

The  presence  of  boron  trioxide  is  a  remarkable  feature  of 
this  mineral.  The  colorless,  red,  and  pale-greenish  kinds 
usually  contain  lithia.  B.  B.  the  darker  varieties  fuse  with 
ease,  and  the  lighter  with  difficulty.  On  mixing  the 
powdered  mineral  with  potassium  bisulphate  and  fluor  spar, 
and  heating  B.B.,  the  flame  becomes  green  owing  to  the 
boron. 

Diff.  The  test  for  boron  is  good  for  all  varieties.  The 
dark  generally  are  readily  distinguished  by  the  lustre, 
absence  of  distinct  cleavage,  and  rather  difficult  fusibility. 
The  black  appear  pitch-black  on  a  surface  of  fracture,  and 
have  not  the  cleavage  lines  of  surfaces  characterizing  prisms 
of  hornblende.  The  brown  resemble  garnet  or  idocrase, 
but  are  less  fusible.  The  red,  green,  and  yellow  varieties 
are  distinguished  readily  by  the  crystalline  form,  the  prisms 
of  tourmaline  always  having  3,  6,  9,  or  12  prismatic  sides 
(or  some  multiple  of  3).  The  electric  properties  of  the 
crystals,  when  heated,  is  another  remarkable  character  of 
this  mineral. 

Obs.  Common  in  granite,  gneiss,  mica  schist,  chlorite 
schist,  steatite,  quartzyte,  and  granular  limestone;  usually 
in  crystals  penetrating  the  rock.  The  black  crystals  are 
at  times  a  foot  long  when  perhaps  of  no  larger  dimensions 
than  a  pipe-stem,  or  even  more  slender.  Has  also  been 
observed  in  sandstones  near  basaltic  or  trap  dikes.  Some- 
times penetrating  quartz  crystals  in  acicular  crystals,  like 
rutile. 

Red  and  green  tourmalines,  over  an  inch  in  diameter  and 

transparent,  have  been  obtained  at  Paris,  Me.,  besides  pink 

and  blue  crystals;  fine  also  at  Auburn,  Hebron,  Norway, 

Rumf  ord,  Andover,  Me. ;  also,  of  much  less  beauty  and  size, 

to 


306  DESCRIPTIONS   OF   MINERALS. 

at  Chesterfield  and  Goshen,  Mass. ;  black  at  Norwich,  New 
Braintree,  and  Carlisle,  Mass. ;  Alsted,  Acworth,  and  Sad- 
dleback Mountain,  N.  H.;  Haddam  and  Monroe,  Ct.; 
Pierpont,  Saratoga,  Port  Henry,  and  Edenville,  N.  Y.; 
Franklin  and  Newton,  .N.  J.;  colorless  and  brown  at 
Dekalb,  N.  Y. ;  transparent  brown  at  Hunterstown, 
Canada;  amber-colored,  at  Fitzroy;  beautiful  greenish  yel- 
low, at  G.  Calumet  I. ;  fine  cinnamon-brown  near  Gouver- 
neur,  Schroon,  Canton,  etc.,  northern  N.  Y.;  Kingsbridge 
and  Amity,  Orange  Co.,  N.  Y. ;  and  in  Sussex  Co.,  N.  J.; 
gray,  bluish  gray,  and  green  at  Edenville,  N.  Y. ;  yellowish, 
bluish,  and  brownish  green  at  London  Grove,  and  near 
Unionville,  Pa.;  black  or  dark  brown,  at  Orford,  N.  H. ; 
yellow  in  E.  Marlboro'  and  W.  Marlboro',  Pa.;  black  at 
Leiperville  and  Marple,  Pa. ;  thin  black  plates,  in  mica,  at 
Graf  ton,  N.  H. ;  Franklin  and  Newton,  Sussex  Co.,  N.  J. 

The  word  tourmaline  is  a  corruption  of  the  name  used  in 
Ceylon,  whence  it  was  first  brought  to  Europe.  Lyncurium 
is  supposed  to  be  the  ancient  name  for  common  tourmaline; 
and  the  red  variety  was  probably  called  hyacinth. 

The  red  tourmalines',  when  transparent  and  free  from 
cracks,  are  of  great  value  and  afford  gems  of  remarkable 
beauty.  They  have  the  richness  of  color  and  lustre  belong- 
ing to  the  ruby.  The  yellow  tourmaline,  from  Ceylon,  is 
hardly  inferior  to  the  real  topaz,  and  is  often  sold  for  that 
gem.  The  green  specimens,  when  clear  and  fine,  are  also 
valuable  for  gems.  Plates  from  pellucid  crystals  cut  in  the 
direction  of  a  vertical  plane  are  much  used  for  polariscopes, 
and  crystals  in  mica  are  often  thus  flattened  and  ready  for 
such  use  when  not  too  thin  or  opaque. 

Cappelenite.  Yttrium-barium  silico  borate,  with  14*16  p.  c.  of 
silica;  hexagonal;  brown;  G.  =  4 '4.  Norway. 

Gehlenite.  Tetragonal,  like  the  scapolites  in  form;  color  grayish 
green  to  brown;  G.  =  2'9-3'07;  formula  Ca^AlO.oSia  with  some  of 
the  Al  replaced  by  3?e,  and  some  of  the  Ca  by  Fe  and  Mg.  Silica 
about  30  per  cent.  Mount  Monzoni,  in  the  Fassa  Valley. 

Andalusite. 

Orthorhombic  ;  I/\I  =  90°  48'.  In  prisms  that  are 
nearly  square.  Cleavage  lateral;  sometimes  distinct.  Also 
massive;  indistinctly  coarse  columnar,  never  fine  fibrous. 

Colors  gray  and  flesh-red,  pink.     Lustre  vitreous,  or  in- 


SUBSILICATES.  307 

clining  to  pearly.    Translucent  to  opaque.    Tough.     H.  = 
7'5.     G.  =3-1-3-3. 


2. 


Composition.  A106Si  =  Silica  36-9,  alumina  63 -1  =  100. 
B.  B.  infusible.  Ignited  after  being  moistened  with  cobalt 
nitrate  assumes  a  blue  color.  Insoluble  in  acids. 

Chiastolite  or  Made  has  an  internal  tessellated  or  cruci- 
form structure.  Figures  1  to  4  represent  sections  of  crystals 
from  Lancaster,  Mass.  The  structure  is  owing  to  carbona- 
ceous impurities  distributed,  in  the  crystallizing  process, 
in  a  regular  manner  along  the  sides,  edges  and  diagonals 
of  the  crystal.  Hardness  sometimes  as  low  as  3. 

Diff.  Distinguished  from  pyroxene,  scapolite,  spodumene, 
and  feldspar  by  its  infusibility,  hardness,  and  form. 

Obs.  Observed  only  in  imbedded  crystals.  Most  abundant 
in  clay  slate  and  mica  slate,  but  occurring  also  in  gneiss. 
The  Tyrol;  Saxony;  Bavaria;  etc.;  also  in  Westf ord,  Mass. ; 
Litcnfield  and  Washington,  Ct. ;  Bangor,  Gorham,  Standish, 
Me.;  Leiperville,  Marple,  and  Springfield,  Pa.,  at  Upper 
Providence,  Pa.,  one  crystal  weighing  7  Ibs.;  as  chiastolite 
at  Sterling  and  Lancaster,  Mass. ;  near  Bellows  Falls,  Vt. ; 
Chowchilla  River,  Mariposa  Co.,  CaL  First  found  at  An- 
dalusia in  Spain. 

Fibrolite.— Sillimanite.     Bucholzite. 

Orthorhombic;  I/\I=  96°-98°.  In  long,  slender  rhom- 
bic prisms,  often  much  flattened,  penetrating  the  gangue. 
Cleavage  macrodiagonal,  brilliant  and  easy.  Also  in 
masses,  consisting  of  aggregated  crystals  or  fibres:  Color 
hair-brown  or  grayish  brown.  Lustre  vitreous,  inclining 
to  pearly.  Translucent  crystals  break  easily.  H.  =  6-7. 
G.  =3-2-3-3. 

Composition.  A105Si,  as  for  andalusite,  =  Silica  36*9, 
alumina  63*1  =  100.  Moistened  with  cobalt  nitrate  and 
ignited  assumes  a  blue  color.  Infusible  alone  and  with 
borax. 

Diff.  Distinguished  from  tremolite  and  the  varieties-  gen- 
erally of  hornblende  by  its  brilliant  diagonal  cleavage,  and 


308  DESCRIPTIONS   OF   MINERALS. 

its  infusibility;  from  kyanite  and  andalusite  by  its  brilliant 
cleavage,  its  fibrous  structure,  and  its  orthorhombic  crys- 
talline form. 

Obs.  Found  in  gneiss,  mica  schist,  and  related  metamor- 
phic  rocks.  Occurs  in  the  Tyrol;  at  Bodenmais  in  Bavaria; 
at  the  White  Mountain  Notch  in  N.  H. ;  at  Chester  and 
near  Norwich,  Ct.,  both  in  crystals,  fibrous,  and  fibrous 
massive;  Yorktown,  N.  Y.;  Chester,  Birmingham,  Concord, 
Darby,  Pa. ;  in  N.  Carolina;  and  elsewhere.  Fibrolite  was 
much  used  for  stone  implements  in  Western  Europe  in  the 
"Stone  age;"  the  locality  whence  the  material  was  derived 
is  not  known. 

Davreuxite.  Infusible.  Probably  impure  fibrolite. 
Dumortierite.  A  related  species,  from  near  Lyons. 
JEhnpholite.  Infusible,  and  may  belong  here.  Sweden. 

Oyanite.— Kyanite.     Disthene. 

Triclinic.  Usually  in  long  thin-bladed  crystals  aggre- 
gated together,  or  penetrating  the  gangue.  Sometimes  in 
short  and  stout  crystals.  Lateral  cleavage  distinct.  Some- 
times fine  fibrous. 

Color  usually  light  blue,  sometimes  having  a  blue  centre 
with  a  white  margin;  sometimes  white,  gray,  green,  or  even 
black.  Lustre  of  flat  face  a  little  pearly.  H.  =  5-7*5, 
greatest  at  the  ends  of  the  prisms,  and  least  on  the  flat  face. 
G.  i  3-55-3 -7. 

Composition.  A10?Si  (=  A103  -f-  Si02),  as  for  andalusite, 
=  Silica  36 '9,  alumina  63*1  =  100.  Blowpipe  characters 
like  those  of  andalusite. 

Diff.  Distinguished  by  its  infusibility  from  varieties  of 
the  hornblende  family.  Short  crystals  have  some  resem- 
blance to  staurolite,  but  their  sides  and  terminations  are 
usually -irregular;  they  diifer  also  in  cleavage  and  lustre. 
The  thin-bladed  habit  of  cyanite  is  very  characteristic. 

Obs.  Found  in  gneiss  and  mica  schist,  and  often  accom- 
panied by  garnet  and  staurolite. 

Occur:;  in  long-bladed  crystallizations  at  Chesterfield  and 
Worthington,  Mass.;  at  Litchfield  and  Washington,  Ct.; 
Windham,  Me.;  Derby  Creek,  Delaware  Co.,  and  E.  Brad- 
ford, Chester  Co.,  Pa.;  near  Wilmington,  Del. ;  and  in  Buck- 
ingham, and  Spotsylvania  cos.,  Va.;  Chubb's  and  Crowder's 
Mts.,  Gaston  Co.,  N.  0.  Short  crystals  (sometimes  called 


SUBSILICATES. 


309 


improperly  fibrolite]  occur  in  gneiss  at  Bellows  Falls,  Vt., 
and  at  Westfield  and  Lancaster,  Mass. 

In  Europe,  at  St.  Gothard  in  Switzerland;  at  Greiner  and 
Pfitsch.in  the  Tyrol;  Styria;  Carinthia;  Bohemia.  Villa  Rica 
in  S.  America  affords  fine  specimens. 

Named  from  the  Greek  kuanos,  a  dark-blue  substance. 
Also  called  Disthene,  in  allusion  to  the  unequal  hardness  in 
different  directions,  and  when  white,  Rhmtizite. 

Kyanite  is  sometimes  used  as  a  gem,  and  has  some  re- 
semblance to  sapphire. 

Topaz. 

Orthorhombic;  I  /\I—  124°  17'.  Rhombic  prisms,  usu- 
ally differently  modified  at  the  two  extremities.  Cleavage 
perfect  parallel  to  the  base. 

Color  pale  yellow;  sometimes  white,  greenish,  bluish,  or 
reddish.  Streak  white.  Lustre  vitreous.  Transparent  to 
subtranslucent.  Pyro-electric.  H.  =8.  G.  3  -4-3  '65. 

Composition.  A10&Si,  with  a  part  of  the  oxygen  replaced 
by  fluorine  =  Silica  16*2,  silicon  fluoride  281,  alumina  55*7 


1. 


=  100.  An  analysis  of  one  specimen  afforded  Silica  34*24, 
alumina  57*45,  fluorine  14*99.  Including  the  fluorine,  the 
formula  is  AlF204Si,  Fa  replacing  1  of  oxygen.  B.B.  infusi- 
ble; some  kinds  become  yellow  or  of  a  pink  tint  when  heated; 
moistened  with  cobalt  nitrate  and  ignited  assumes  a  fine 
blue  color.  Insoluble  in  acids. 

Diff.  Readily  distinguished  from  the  minerals  it  resem- 
bles by  its  brilliant  and  easy  basal  cleavage. 

Obs.  Pycnite  has  a  thin  columnar  structure  and  forms 
masses  imbedded  in  quartz.  The  Physalite  or  Pyropliysa- 
lite  of  Hisinger  is  a  coarse,  nearly  opaque  variety,  found  in 
yellowish- white  crystals  of  considerable  dimensions;  intu- 
mesces  when  heated,  and  hence  the  name  from  phusao,  to 
blow,  and  pur,  fire.  Topaz  occurs  altered  to  mica  (da- 
mourite). 


310  DESCRIPTIONS   OF   MINERALS. 

Confined  to  metamorphic  rocks  or  to  veins  intersecting 
them,  and  often  associated  with  tourmaline,  beryl,  and  oc- 
casionally with  apatite,  fluorite,  and  tin  ore. 

Fine  topazes  are  brought  from  the  Uralian  and  Altai 
mountains,  Siberia,  and  from  Kamschatka,  where  they  occur 
of  green  and  blue  colors.  In  Brazil  they  are  found  of  a 
deep  yellow  color,  either  in  veins  or  nests  in  lithomarge,  or 
in  loose  crystals  or  pebbles.  Sky-blue  crystals  have  been 
obtained  in  th,e  district  of  Cairngorm,  in  Aberdeen  shire. 
The  tin-mines  of  Schlackenwald,  Zinnwald,  and  Ehren- 
friedersdorf  in  Bohemia,  St.  Michael's  Mount  in  Cornwall, 
etc.,  afford  smaller  crystals.  The  physalite  variety  occurs 
in  crystals  of  immense  size  at  Finbo,  Sweden,  in  a  granite 
quarry,  and  at  Broddbo.  A  well-defined  crystal  from  this 
locality,  in  the  possession  of  the  College  of  Mines  of  Stock- 
holm, weighs  eighty  pounds.  Altenberg  in  Saxony  is  the 
principal  locality  of  pycnite;  it  is  there  associated  with 
quartz  and  mica. 

At  Stoneham,  Me.,  in  fine  crystals;  Trumbull,  Ct.,  in 
large  coarse  crystals,  sometimes  6  to  7  in.  through,  and 
rarely  small  and  transparent ;  Pike's  Peak,  Col. ,  in  fine 
crystals,  some  affording  cut  stones  10  to  193  carats  each  ; 
also  in  Chalk  Mt.  and  Nathrop,  Col.,  in  rhyolyte ;  in 
Utah,  in  rhyolyte,  40  m.  N.  of  Sevier  Lake;  Arizona;  Ore- 
gon, in  gold- washings. 

The  ancient  topazion  was  found  on  an  island  in  the  Red 
Sea,  which  was  often  surrounded  with  fog,  and  therefore 
difficult  to  find.  It  was  hence  named  from  topazo,  to  seek. 
This  name,  like  most  of  the  inineralogical  terms  of  the  an- 
cients, was  applied  to  several  distinct  species.  Pliny 
describes  a  statue  of  Arsinoe,  the  wife  of  Ptolemy  Philadel- 
phus,  four  cubits  high,  which  was  made  of  topazion,  or 
topaz,  but  evidently  not  the  topaz  of  the  present  day,  nor 
chrysolite,  which  has  been  supposed  to  be  the  ancient  topaz. 
It  has  been  conjectured  that  it  was  a  jasper  or  agate;  others 
have  supposed  it  to  be  prase  or  chrysoprase. 

Topaz  is  employed  in  jewelry,  and  for  this  purpose  its 
color  is  often  altered  artificially  by  heat.  The  variety  from 
Brazil  assumes  a  pink  or  red  hue,  so  nearly  resembling  the 
Balas  ruby,  that  it  can  only  be  distinguished  by  the  facility 
with  which  it  becomes  electric  by  friction.  Beautiful 
crystals  for  the  lapidary  are  brought  from  Minas  Novas,  in 


SUBSILICATES.  311 

Brazil.     From  their  peculiar  limpidity,  topaz  pebbles  are 
sometimes  denominated  gouttes  d'eau. 

On  account  of  the  perfect  cleavage,  topaz  is  a  poor  sub- 
stitute for  emery. 

Euclase. 

Monoclinic.  In  oblique  rhombic  prisms,  with  cleavage 
highly  perfect  parallel  to  the  clinodiagonal  section,  afford- 
ing smooth  polished  faces. 

Color  pale  green  to  white  or  colorless,  pale  blue.  Lustre 
vitreous;  transparent.  Brittle.  H.  =:  7*5.  Gr.  =  3*1. 
Pyro-electric. 

Composition.  H2fBe2A10]0Si2  =  Silica  41-20,  alumina 
35-22,  glucina  17 '39,  water  6-19  =  100.  B.B.  fuses  with 
much  difficulty  to  a  white  enamel;  not  acted  on  by  acids. 

Diff.  The  cleavage  of  this  glassy  mineral  is  very  perfect, 
like  that  of  topaz,  but  is  not  basal. 

Obs.  The  Ural;  Tyrol;  with  topaz  in  Brazil. 

The  crystals  are  elegant  gems  of  themselves,  but  are 
seldom  cut  for  jewelry  on  account  of  their  brittleness. 

Datolite.— Datholite.     Humboldtite. 

Monoclinic;  I/\I=  115°  3'.  Crystals  small  and  glassy, 
without  distinct  cleavage. 
Also  botryoidal,  and  columnar 
within  (botryolite);  also  mas- 
sive and  porcelain-like  in 
fracture.  Color  white,  occa- 
sionally grayish,  greenish,  yel- 
lowish, or  reddish.  Trans- 
lucent. H.  =  5-5-5.  G.  = 
2-9-3. 

Composition.  H2Ca2B2010Sia 
=  Silica  37'5,  boron  trioxide  21  '9,  lime  35*0,  water  5 '6  = 
100.  Botryolite  contains  twice  the  proportion  of  water. 
B.B.  becomes  opaque,  intumesces  and  melts  easily  to  a 
glassy  globule  coloring  the  flame  green.  Decomposed  by 
hydrochloric  acid;  the  solution  gelatinizes  on  evaporation. 

Diff.  Its  glassy  complex  crystallizations,  without  cleav- 
age, distinguish  it  from  other  minerals  that  gelatinize  with 
acid;  so  also  its  tingeing  the  blowpipe-flame  green. 

Obs.  Occurs  in  cavities  in  trap  rocks,  or  the  adjoining 
sandstone,  and  in  gneiss.  Found  in  Scotland;  at  Andreas- 


312 


DESCRIPTIONS   OF   MINERALS. 


berg;  Baveno;  Toggiana.  Also  at  Bergen  Hill,  IN".  J.;  at 
Roaring  Brook,  14  miles  from  New  Haven;  and  near  Hart- 
ford, Berlin,  Middlefield  Falls,  Meriden,  Tariff ville,  Gt.; 
in  great  abundance  at  Eagle  Harbor  in  the  copper  region, 
Lake  Superior,  both  in  crystals  and  massive;  on  Isle  Royale; 
near  San  Carlos,  Cal. 

Homilile.  A  black  silicate  of  iron  and  calcium,  like  datolite  in  its 
crystals;  resembles  gadolinite,  but  affords  15  to  18  per  cent,  of  boracic 
acid  with  32  of  silica;  formula  R3B2Oi0Si2.  Brevig,  Norway. 

Titanite. — Sphene. 

Monoclinic;  7  A  /=  113°  31',  2/\2  =  J36 
usually  very  oblique  thin-edged  prisms. 

1.  2. 


crystals 
in  one 


direction  sometimes  perfect,  owing  to  twin-composition. 
Occasionally  massive. 

Color  grayish  brown,  ash-gray,  brown  to  black;  some- 
times pale  yellow  to  green.  Streak  uncolored.  Lustre 
adamantine  to  resinous.  Transparent  to  opaque.  H.  = 
5-5-5.  G,  =3-4-3-56. 

Composition.  CaTiOESi  =  Silica  30'6,  titanium  dioxide 
40*82,  lime  28*57  =  100;  in  dark  brown  and  black  crystals, 
some  iron  replaces  part  of  the  calcium.  B.B.  fuses  with 
intumescence.  Imperfectly  decomposed  by  hydrochloric 
acid. 

The  dark  varieties  of  this  species  were  formerly  called 
titanite,  and  the  lighter  sptiene.  Named  sphene  from  the 
wedge-shaped  crystals,  from  the  Greek  splien,  wedge. 
Oreenovite  is  a  variety  colored  rose-red  by  manganese. 
Leucoxene  and  Titanomorph ite  are  probably  titanite (p.  453). 

Diff.  The  thin  wedge-like  form  of  the  crystals  is  gener- 
ally a  distinguishing  character;  but  some  crystals  are  of 
other  forms. 

Obs.  Occurs  mostly  in  disseminated  crystals  in  granite, 


SUBSILICATES. 


313 


gneiss,  mica  schist,  syenyte,  or  granular  limestone.  Usually 
associated  with  pyroxene  and  scapolite,  and  often  with 
graphite.  Has  been  found  in  volcanic  rocks.  Crystals  are 
commonly  |  to  |  an  inch  long ;  but  sometimes  very  large. 

Foreign  localities  are  Arendal  in  Norway;  St.  Gothard, 
Mont  Blanc;  Tyrol;  Piedmont;  Argyleshire  and  Galloway, 
Great  Britain.  Occurs  at  Roger's  Rock,  on  Lake  George, 
with  graphite  and  pyroxene,  at  Gouverneur,  near  Natural 
Bridge  in  Lewis  Co.  (the  variety  called  Lederite),  in  Mon- 
roe, Edenville,  Warwick,  and  Amity,  in  Orange  Co.,  near 
Peekskill  in  Westchester  County,  and  near  West  Farms, 
N.  Y.;  Lee,  Bolton,  and  Pelham,  Mass.;  Trumbull,  Ct.; 
Sanford  and  Thomaston,  Me. ;  Franklin,  N.  J. ;  near  Attle- 
boro',  Bucks  Co.,  Pa.;  at  Dixon's  quarry,  7  miles  from 
Wilmington,  Del.;  25  miles  from  Baltimore,  Md.,  on  the 
Gunpowder;  Renfrew,  Canada,  in  enormous  crystals,  one 
weighing  72  pounds. 

Alshedite,  from  Sweden,  is  probably  brown  and  gray  titanite. 

Guarinite.     Like  sphene  in  composition,  but  orthorhombic. 

Keilhauite,  or  Ytlro-titanite.  Related  to  sphene;  brownish  black, 
with  a  grayish  brown  powder;  G.  =  3*69;  H.  =  6  5;  fuses  easily; 
affords  Silica  30;0,  titanic  acid  29 '0,  yttria  9 '6,  lime  18 '9,  iron  sesqui- 
oxide  6 '4,  alumina  6*1;  also  contains  scandium.  Arendal,  Norway. 

Tscheffkinite.    Near  Keilhauite.     Illmen  Mountains. 

St  aurolite. — Staurotide. 

Orthorhombic  ;  1  A  /=  129°  20'.     Cleavage  imperfect. 
Usually  in  cruciform   twin  crystals. 
Figure  2,  common ;  another  crosses 
at  an  acute  angle  near  60°;  another, 
of  rare  occurrence,  consists  of  three 
crystals  intersecting  at  angles  near 
60°.      Never   in   massive  forms    or 
slender  crystallizations. 
Color  brown  to   black.     Lustre  vitreous,  inclining  to 
resinous;  sometimes  bright,  but  often  dull.     Translucent 
to  opaque.     H.  =  7-7*5.     G.  =  3-4-3-8;  purest,  3-7-3-8. 

Composition.  (|R3£Al)40]8Si3,  in  which  R  =  iron  with  a 
little  magnesium,  and  occasionally  manganese,  with  some 
hydrogen  of  basic  water.  Silica  28*3,  alumina  51 '7,  iron 
protoxide  15 -8,  magnesia  2'5,  water  1*7=  100.  B.B.  in- 
fusible, excepting  a  manganesian  variety.  Insoluble  in 
acids. 


314  DESCRIPTIONS    OF    MINERALS. 

Dijf.  Distinguished  from  tourmaline  and  garnet  by  its 
inf usibility  and  form. 

Obs.  Found  in  crystals  in  mica  schist  and  gneiss. 

Very  abundant  through  the  mica  schist  of  New  England: 
Grantham,  Cabot,  AVindham,  Me.;  Franconia,  Lisbon, 
N.  H.;  Chesterfield,,  Mass.;  Bolton,  Tolland,  Salisbury, 
Ct  ;  on  the  Wissahickon,  8  m.  from  Philadelphia;  in 
Cherokee,,  Madison  and  Clay  cos.,  N.  C.;  at  Canton,  and 
in  Fannin  Co.,  Ga.,  in  handsome  twins.  Mt.  Campione  in 
Switzerland,  and  the  Greiner  Mountain,  Tyrol,  are  noted 
foreign  localities. 

Named  staurolite  from  the  Greek  stauros,  a  cross. 

Schorlomite.  Black,  and  often,  irised  tarnished ;  streak  grayish 
black;  H.  =  7-7 '5;  G.  =  8  80;  fuses  readily  on  charcoal;  easily  de- 
composed by  the  acids,  and  gelatinizes;  contains  much  titanium,  with 
iron,  lime,  and  silica.  Magnet  Cove,  Ark.;  Kaiserstuhlgebirge, 
Breisgau.  Makes  a  black  gem  of  submetallic  lustre. 

Zunyite.  In  tetrahedrons,  often  transparent,  and  massive ;  lustre 
vitreous;  H.  =  7;  Gr.  =  2'875;  analysis  afforded  Silica  24'33,  alum- 
ina 57'88,  water  (basic)  10'89,  fluorine  5'61,  chlorine  2'91,  with  a  little 
FeO3,  K2O,  Na2O,  Li2O.  The  Zuni  Mine,  San  Juan  Co.,  Col. 

B.    HYDROUS   SILICATES. 

The  three  sections  under  which  the  Hydrous  Silicates 
are  arranged  are  the  following  : 

I.  GENERAL  SECTION.     Includes:  (I)  Bisilicates — Pec- 
tolite,  Laumontite,   Apophyllite,  etc.;    (2)    Unisilicate* — 
Prehnite,  Calamine,  etc.;  and  (3)    Subsilicates — as  Allo- 
phane,  and  some  related  species. 

II.  ZEOLITE    SECTION.      Includes  minerals  which  are 
feldspar-like  in  constituents,  and  apparently  so  in  quantiv- 
alent  (or  oxygen)  ratio;  the  basic  elements  being,  as  in  the 
feldspars,  (1)  aluminium,  and  (2)  the  metals  of  the  alkalies 
K,  Na,  and  of  the  alkaline  earths  Ca,  Ba,  with  also  Sr,  to 
the  almost  total  exclusion  of  magnesium  and  iron. 

III.  MARGAROPHYLLITE    SECTION.     Embraces  species 
having  a  micaceous  or  thin-foliated  structure  when  crystal- 
lized, with  the  surface  of  the  folia  pearly,  and  the  plane 
angle  of  the  base  of  the  prism  120°.     Whether  crystallized 
or  massive,  the  feel  is  greasy,  at  least  when  pulverized. 
It  comprises  (1)  Bisilicates:  including  Talc  and  Pyrophyl- 
lite,  which  are  atomically  and  physically  similar  species, 
although  the  former  is  a  magnesium  silicate,  and  the  latter 


HYDROUS   SILICATES — GENERAL   SECTION.  315 

an  aluminium  silicate;  (2)  Non-alkaline  Unisilicates,  in- 
cluding Kaolinite  and  Serpentine,  which  have  a  similar 
difference  in  constituents  to  the  preceding  with  the  same 
likeness  in  composition,  and,  also,  some  related  species;  (3) 
Alkaline  Unisilicates  :  as,  Finite  and  the  Hydrous  Micas, 
which  are  species  containing  potassium  or  sodium  as  an 
essential  constituent;  (4)  the  Chlorite  Group,  the  species 
of  which  are  mostly  Subsilicates  and  non-alkaline. 

I.  GENERAL  SECTION. 
Pectolite. 

Monoclinic,  isomorphous  with  wollastonite.  Usually  in 
aggregations  of  acicular  crystals,  or  fibrous-massive,  radiate, 
stellate.  Color  white,  or  grayish.  Translucent  to  opaque. 
Tough.  H.  =  5.  G.  =  2-86-2-88. 

Composition.  K03Si,  in  which  R  =  |H2£Na2£  Ca,  =  Silica 
54-2,  lime  33 -8,  soda  9-3,  water  2*7  =  100.  In  the  closed 
tube  yields  water.  B.B.  easily  fusible'.  Decomposed  by 
hydrochloric  acid,  and  the  solution  gelatinizes  on  evapora- 
tion. 

Resembles  fibrous  varieties  of  tremolite,  natrolite,  thom- 
sonite,  wollastonite. 

Obs.  Occurs  mostly  in  cavities  or  coamc  in  trap  or  basic 
eruptive  rocks,  and  occasionally  in  other  rocks.  Found 
at  Ratho  Quarry,  Edinburgh,  Scotland  (Ratholite,  Walker- 
ite) ;  at  Kilsyth ;  Isle  of  Skye ;  the  Tyrol ;  Bcrgon  Hill, 
N.  J.;  compact  at  I.  Royale,  L.  Superior,  and  near  Point 
Barrow,  Alaska. 

Okenite.  Gyrolite.  Related  hydrous  calcium  silicates.  Okenite  is 
from  the  Faroe  Islands,  Iceland,  and  Greenland,  and  gyrolite  from 
the  Isle  of  Skye,  and  from  Nova  Scotia,  20  m.  S.  \f.  of  Cape  Blomi- 
don.  Tobermorite,  from  Isle  of  Mull,  is  near  gyrolite. 

Laumontite. 

Monoclinic;  I/\I  =86°  16'.  Near  pyroxene  in  form. 
Cleavage:  clinodiagonal,  and  parallel  to  /,  perfect.  Also 
massive,  with  a  radiating  or  divergent  structure;  not  fine 
fibrous. 

Color  white,  passing  into  yellow  or  gray,  sometimes  red. 
Lustre  vitreous,  inclining  to  pearly  on  the  cleavage  face. 
Transparent  to  translucent.  H.  =  3  -5-4.  G.  =  2  -25-2  -36. 
Becomes  opaque  on  exposure  through  loss  of  water,  and 
readily  crumbles. 


316  DESCHIPTIOXS   OF  MINERALS. 

Composition.  CaA10]0Si4  +  4  aq  =  Silica  50*0,  alumina 
21-8,  lime  11-9,  water  16-3  =  100.  B.B.  swells  up  and  fuses 
easily  to  a  white  enamel.  Decomposed  by  hydrochloric 
acid,  and  the  solution  gelatinizes  on  evaporation. 

Diff.  The  alteration  this  species  undergoes  on  exposure 
to  the  air  at  once  distinguishes  it.  This  result  may  be 
prevented  with  cabinet  specimens  by  dipping  them  into  a 
solution  of  gum-arabic. 

Obs.  Found  in  the  veins  and  cavities  of  trap-rocks  and 
also  in  gneiss,  porphyry.  Occurs  at  the  Faroe  Islands;  Kil- 
patrick  Hills,  near  Glasgow;  Disco,  Greenland;  St.  Gothard, 
Switzerland;  Peter's  Point,  N.  Scotia;  Phippsburg,  Me.; 
Charlestown  syenyte  quarries,  Mass.;  Bergen  Hill,  N.  J.; 
the  Copper  region,  L.  Superior,  and  Isle  Royale. 

Leonhardite.  Probably  Laumontite  which  has  lost  part  of  its  water 
by  alteration— the  part  that  goes  off  below  212°  F.  Resembles  that 
species  in  crystallization  and  in  most  of  its  characters,  but  differs  in 
being  less  efflorescent  on  exposure  to  a  dry  atmosphere.  Analyses  of 
specimens  from  Copper  Falls,  Lake  Superior,  obtained,  Silica  55'50, 
alumina  21'19,  lime  10  56,  water  11  93  =  99'68.  The  Copper  Falls 
variety  alters  little  on  exposure.  Reported  also  from  trachyte  at 
Schemnitz,  Hungary;  Pfitsch  in  the  Tyrol. 

Apophyllite. 

Tetragonal.     In  square  octahedrons,  prisms,  and  tables. 

Cleavage  parallel  with  the  base  highly  perfect.     Massive 
3  and  foliated.    Color  white  or 

grayish;  sometimes  with  a 
shade  of  green,  yellow,  or 
red.  Lustre  of  0  pearly:  of 
the  other  faces  vitreous. 
Transparent  to  opaque.  H. 
=  4-5-5.  G.  =  2-3-2-4. 

Composition.  Silica  52 -97, 
lime  24  72,  potash  5*20,  water 
15-90,  fluorine  2 -10  =  100-89. 
B.B.  exfoliates,  colors  the 
flame  violet  (owing  to  the 
potash),  and  fuses  very  easily 

to  a  white  enamel.     In  the  closed  tube  yields  water  which 

has  an  acid  reaction.     Decomposed  by  hydrochloric  acid 

with  the  separation  of  slimy  silica. 
Diff.  The  easy  basal  cleavage  and  basal  pearly  lustre,  and 

the  forms  of  its  crystals,  distinguish  it  from  the  preceding 


HYDROUS   SILICATES — GENERAL   SECTION.  317 

species.  The  prisms  are  sometimes  almost  cubes,,  with  the 
angles  cut  off  by  the  planes  of  the  pyramid;  but  the  differ- 
ence in  the  lustre  of  the  prismatic  and  basal  faces  shows 
that  it  is  tetragonal.  It  is  never  fibrous. 

The  name  alludes  to  its  exfoliation  before  the  blowpipe. 

Obs.  Found  in  amygdaloidal  trap  and  basalt. 

Fine  crystallizations  at  Peter's  Point  and  Partridge 
Island,  N.  Scotia;  Bergen  Hill  and  Weehawken,  N.  J.; 
Cliff  Mine,  L.  Superior  region. 

Catapleiite.     Hydrous  zirconium  sodium  silicate.    Norway. 

Dioptase  and  Ckrysocolla.     Hydrous  copper  silicates.     See  p.  156. 

Picrosmine,  Pyrallolite,  Picrophyll,  Traversellite,  Pitkarandite,  Stra- 
konitzite,  Monradite,  are  names  of  varieties  of  pyroxene  in  different 
stages  of  alteration.  Xylotine  and  Pilolite  are  probably  altered  as- 
bestus. 

Leidyite.  A  hydrous  bisilicate  of  Al,  Fe,  Mg,  Ca;  in  silky  greenish 
scales.  From  Leiperville,  Pa. 

Prehnite. 

Orthorhombic;  /A  /=  99°  56'.  Cleavage  basal.  Some- 
times in  six-sided  prisms,  rounded  so  as  to  be  barrel-shaped, 
and  looking  as,if  made  up  of  a  series  of  united  plates;  also 
in  thin  rhombic  or  hexagonal  plates.  Usually  reniform 
and  botryoidal,  with  a  crystalline  surface.  Never  fibrous. 

Color  apple-green  to  colorless.  Lustre  vitreous,  except 
the  face  0,  which  is  somewhat  pearly.  Subtransparent  to 
translucent.  H.  =  6-6-5.  G.  =  2 -8-2 -96. 

Composition.  H2Ca2A10J2Si8  =  Silica  43-6,  alumina  24'9, 
lime  27%  water  4-4  =  100.  B.B.  fuses  very  easily  to  an 
enamel-like  glass.  Decomposed  by  hydrochloric  acid,  leav- 
ing a  residue  of  silica,  but  does  not  gelatinize.  Yields  a 
little  water  when  heated  in  a  closed  tube. 

Diff.  Distinguished  from  beryl,  green  quartz,  and  chalce- 
dony by  fusing  B.B.,  and  from  the  zeolites  by  its  hardness. 

Obs.  Found  in  the  cavities  of  trap,  gneiss,  and  granite. 

Occurs  in  trap  in  the  Connecticut  Valley,  and  at  Pater- 
son  and  Bergen  Hill,  N.  J. ;  in  gneiss  at  Bellows  Falls,  Vt. ; 
in  syenyte  at  Charlestown,  Mass. ;  and  very  abundant,  form- 
ing large  veins,  in  the  Copper  region  of  Lake  Superior, 
3  miles  south  of  Cat  Harbor,  and  elsewhere,  where  the  green- 
ish variety  called  Chlorastrolite  and  Zonochlorite  is  found. 

The  Fassa  Valley  in  the  Tyrol,  St.  Christophe  in  Dau- 
phiny,  and  the  Salisbury  Crag,  near  Edinburgh,  are  some 
of  the  foreign  localities. 


318  DESCRIPTION'S   OF   MINERALS. 

Prehnite  receives  a  handsome  polish,  and  is  sometimes 
used  for  inlaid  work.  In  China  it  is  polished  for  orna- 
ments, and  large  slabs  have  been  cut  from  masses  brought 
from  there. 

Gumondite  (Zeagonitv).  A  hydrous  calcium  aluminium  silicate,  oc- 
curring in  twinned  crystals.  Found  in  lava  at  Capo  di  Bove,  near 
Rome;  also  near  Gorlitz. 

Edtngtonite.  Tetragonal;  a  hydrous  barium-aluminium  silicate. 
The  Kilpatrick  Hills,  with  harmotome. 

Carpltolite.  A  manganese-aluminium  silicate;  in  silky,  yellow,  radi- 
ated tufts.  Tin-mines  of  Schlackenwald. 

Piliuite.  A  hydrous  calcium-aluminium  silicate ;  in  fibrous  felt- 
like  crusts;  B.B.  fuses  easily;  insoluble  in  hot  acid.  Silesia. 

Matricite.  Hydrous  magnesium  silicate;  gray;  infusible.  Wermland, 
Sweden. 

Pyrosmalite.     A  manganese-iron  silicate  and  chloride.     Sweden. 

Calamine.     A  hydrous  zinc  unisilicate;  see  p.  174. 

Villarsite  is  probably  altered  chrysolite;  see  p.  277. 

Cerite,  Trilomite,  are  cerium  and  lanthanum  silicates.  Thorite  (Or- 
angite),  Eucrasite,  Erdmanmte,  and  Freyalite  are  thorium  silicates. 
Kainoslte,  an  yttrium,  etc.,  silicate. 

Uranothorite.  A  thorite  containing  uranium;  dark  red-brown;  in- 
fusible. Champlain  iron  region,  Northern  New  York. 

Allophane. 

In  amorphous  incrustations,  with  a  smooth  small-mam- 
millary  surface,  and  often  hyalite-like,  and  sometimes  pul- 
verulent. Color  pale  bluish  white  to  greenish,  and  deep 
green;  also  brown,  yellow,  colorless.  Translucent.  H.  =  3. 
G.  =  1-85-1 -89. 

Composition.  Mostly  A105Si  +  6  (or  5)  aq.  Silica  23*75, 
alumina  40-62,  water  35'63  =  100.  In  the  closed  tube 
yields  much  water.  B.B.  infusible,  but  crumbles.  A 
blue  color  with  cobalt  solution,  and  a  jelly  with  hydrochloric 
acid. 

Occurs  in  Saxony;  a  copper-mine  in  Bohemia;  with  lim- 
onite  in  Moravia;  Chessy  Copper  Mine  near  Lyons;  in  Old 
Chalk  Pits  near  Woolwich,  England  ;  with  gibbsite  in 
limonite  beds  in  Richmond,  Mass.;  at  the  copper-mine  of 
Bristol,  Conn. ;  at  Morgantown,  Pa. ;  copper-mines  of  Polk 
County,  Tenn.;  Lawrence  Co.,  Ind. 

Sulphatallophane.  A  mixture  of  allophane  and  a  basic  aluminium 
sulphate. 

Colly  rite.  A  hydrous  aluminium  silicate  containing  only  14  to  15 
per  cent,  of  silica,  and  35  to  40  of  water;  and  Schroiterite  is  another 
•with  11  to  12  per  cent,  of  silica.  The  latter  has  been  reported  as  occur- 


HYDROUS   SILICATES — ZEOLITE    SECTION.  319 

ring  as  a  gum -like  incrustation,  at  the  falls  of  Little  River,  on  Sand 
Mountain,  Cherokee  County,  Alabama.  JScarbroiteis  a  related  mineral 
of  doubtful  nature. 

Leucotile.     A  hydrous  subsilicate.     On  serpentine.     Silesia. 

Chalcomorph^te.  Hexagonal  with  basal  cleavage;  affords  only  25 '4 
p.  c.  of  silica,  with  alumina,  lime,  and  soda.  Lake  Laach;  The  Eiffel. 

/^"  II.   ZEOLITE   SECTION. 

The  species  of  the  Zeolite  Section  have  been  described  as 
having  some  relation  to  the  feldspars  in  constitution.  In 
the  feldspars,  as  explained  on  page£!J%the  following  oxygen 
ratios,  for  the  protoxides,  alumina,  and  silica,  are  the  com- 
mon ones:  1 : 3  : 4,  1 :  3  :  6, 1 : 3  : 8, 1  :  3  :  9, 1  :  3  : 10, 1 : 3  : 12. 
So,  among  the  zeolites,  if  the  water  be  left  out  of  considera- 
tion, these  are  the  ratios:  1 :  3  :  4  (in  Thomsonite),  1:3:6 
(Natrolite,  Scolecite,  etc.),  1 :  3  :  £  (Analcite,  Chabazite, 
etc.),  1 :  3  : 10  (Harmotome),  1 :  3  : 12  (Stilbite,  Heulandite, 
etc.).  This  fact,  added  to  the  absence  or  nearly  total  ab- 
sence of  magnesium  and  iron,  and  presence,  instead,  of  Na2, 
K0,  Ca,  Ba,  make  out  a  distinct  relation  to  the  feldspars, 
whatever  may  be  the  part  which  the  water  sustains  in  the 
compounds.  Besides  barium,  strontium  is  sometimes  pres- 
ent, an  element  not  yet  known  to  characterize  a  species  of 
feldspar. 

These  minerals  were  called  zeolites  because  they  generally 
fuse  easily  with  intumescence  before  the  blowpipe,  the  term 
being  derived  from  the  Greek  zeo,  to  boil.  Among  those 
described  beyond,  Heulandite  and  Stilbite  have  a  strong 
pearly  cleavage,  and  the  latter  is  often  in  pearly  radiations; 
Natrolite,  Scolecite,  are  fibrous  and  radiated,  or  in  very 
slender  prisms;  Thomsonite  occurs  either  radiated,  or  com- 
pact, or  in  short  crystals;  while  Harmotome,  Analcite,  and 
Chabazite,  and  the  related  Gmelinite,  occur  only  in  short 
or  stout  glassy  crystals,  those  of  chabazite  looking  some- 
times like  cubes,  and  of  anal  cite,  like  trapezohedral  garnets 
in  form. 

The  zeolites  are  sometimes  called  trap  minerals,  because 
they  are  often  found  in  the  cavities  or  fissures  of  amygda- 
loidal  trap  as  well  as  related  basic  eruptive  rocks.  Yet 
they  occur  also  occasionally  in  fissures  'or  cavities  in  gneiss, 
granite,  and  other  metamorphic  rocks.  They  are  not  the 
original  minerals  of  any  of  these  rocks;  but  the  results  of 
alteration  of  portions  of  them  near  the  little  cavities  or  fis- 


320  DESCRIPTIONS   OF  MINERALS. 

sures  in  which  the  minerals  occur;  and  part  were  made 
while  the  rock  was  still  hot,  and  as  cooling  went  forward. 
Besides  true  zeolites,  such  cavities  often  contain  also 
Laumontite  (p.  293),  noted  for  its  tendency  to  crumble  on 
exposure;  Pectolite  and  Okenite  (p.  293),  which  are  fibrous 
like  Natrolite  and  Scolecite;  Apophyllite  (p.  294),  having 
one  pearly  cleavage  like  heulandite  and  stilbite;  Prehnite 
(p.  295),  usually  apple-green;  Datolite  (p.  289),  in  stoutish 
glassy  complex  crystals,  or  in  smooth  botryoidal  forms; 
Aragonite  (p.  218),  sometimes  radiated  fibrous,  and  Calcite 
(p.  215)  with  its  three  directions  of  like  easy  cleavage,  and 
effervescing  with  hydrochloric  acid;  Siderite  (p.  185),  in 
spheroidal  or  other  forms;  Chlorite  (p.  316),  granular  mas- 
sive, of  a  dark  olive-green  color;  and  Quartz,  either  in 
crystals,  or  as  chalcedony,  agate,  or  carnelian,  and  in 
either  case  easily  distinguished  by  the  hardness,  absence 
of  cleavage,  and  inf usibility.  Of  all  these  species  Calcite 
and  Quartz  are  the  most  common.  Of  rarer  occurrence 
than  the  above,  there  are  Orthoclase,  Asphaltic  coal,  Cop- 
per, etc. 

All  the  zeolites  yield  water  in  the  closed  tube,  and  many 
of  them  gelatinize  with  hydrochloric  acid. 

Thomsonite. 

Orthorhombic;  /A  /=  90°  26'.  In  right  rectangular 
prisms.  Usually  in  masses  having  a  radiated  structure 
within,  and  consisting  of  long  fibres,  or  acicular  crystals; 
also  amorphous.  Color  snow-white ;  impure  varieties 
brown.  Lustre  vitreous,  inclining  to  pearly.  Transparent 
to  translucent.  H.  =  5-5.  Brittle.  G.  =  2 -3-2 -4. 

Composition.  (Ca,  Na3)A108Si2  +  2J  aq  =  Silica  38-09,  al- 
umina 31  -62,  lime  12-60,  soda  4-62,  water  13-40  =  100-20. 
B.B.  fuses  very  easily  to  a  white  enamel.  Decomposed  by 
hydrochloric  acid;  solution  gelatinizes  on  evaporation. 

Diff.  Distinguished  from  natrolite  by  its  fusion  to  an 
opaque  and  not  to  a  glassy  globule. 

Obs.  Occurs  in  amygdaloid,  near  Kilpatrick,  Scotland; 
at  the  Faroe  Ids.  (Mesolem  Faroelite)  in  spherical,  lamellar 
radiated,  and  pearly  within;  in  lavas  at  Vesuvius  (Compton- 
ite}\  in  clinkstone  in  Bohemia;  the  Tyrol,  etc.;  at  Peter's 
Point,  Nova  Scotia,  in  trap;  a  massive  variety  (Ozarkite)  at 
Magnet  Cove,  Ark. ;  at  Grand  Marais,  L.  Superior,  massive 


HYDROUS   SILICATES— ZEOLITE   SECTION.  321 

and  in  hard  nodules,  radiated  within,  which  have  much 
beauty  when  polished,  and  are  used  in  jewelry. 

The  species  was  named  after  Dr.  Thomas  Thomson,  of 
Glasgow. 

Hydronephelite.  ^  White;  H.  =  4.5;  gelat.  Litchfield,  Me.,  from 
alteration  of  sodalite. 

Natrolite. 

Orthorhombic ;  /  A  /=  91°;  1  A  1  over  *x  =  143°  20'. 
Prisms  very  slender  and  aggregated.  Also  in  globular, 
stellated,  and  divergent  groups  of  delicate 
acicular  fibres,  the  fibres  often  terminating  in 
acicular  prismatic  crystals. 

Color  white,  or  inclining  to  yellow,  gray, 
red.  Lustre  vitreous.  Transparent  to  trans- 
lucent. H.  =  5-5-5.  G.  =  2 -245-2 -25. 
Brittle. 

Composition.  Na2A10,0Si3  +  2  aq  =  Silica 
47-29,  alumina  26-06,  soda  16-30,  water  9  45 
=  100.  B.B.  fuses  easily  and  quietly  to  a  clear  glass;  a 
fine  splinter  melts  in  a  candle  flame.  Decomposed  by  hy- 
drochloric acid;  the  solution  gelatinizes  on  evaporation. 

Diff.  Distinguished  from  scolecite  by  its  quiet  fusion, 
and  also  by  the  characters  mentioned  below. 

Ob*.  Found  in  amygdaloidal  trap,  basalt  and  volcanic 
rocks;  sometimes  in  seams  in  granitic  rocks.  Named  from 
natron,  soda. 

Occurs  in  Bohemia;  Auvergne;  Fassathal,  Tyrol;  at 
Glen  Farg  in  Fifeshire;  in  Dumbartonshire;  Nova  Scotia; 
Bergen  Hill  and  Weehawken,  N.  J. ;  Copper  region,  Lake 
Superior. 

Scolecife.  Resembles  natrolite,  and  differs  in  containing  lime  in  place 
of  stoda  ;  also  in  having  its  slender  rhombic  glassy  prisms  longitudi- 
nally twinned,  as  is  shown  by  the  meeting  of  two  ranges  of  stria?  at  an 
angle  along  or  near  the  central  line  of  opposite  prismatic  planes ; 
crystallization  either  monoclinic  or  triclinic;  lustre  vitreous,  or  a  little 
pearly;  B.B.  curls  up  like  a  worm  (whence  the  name  from  the  Greek 
*kole.P,  a  worm]  and  then  melts.  Staff  a;  FarOe;  Iceland;  Finland; 
Hindostan;  Liguria;  Fel linen  Alp. 

Mexolite.  A  related  species,  similar  in  its  acicular  forms;  monoclinic 
or  triclinic.  Includes  Antrimolite  and  Harringlonite.  Occurs  on 
Fiiroe,  at  Giant's  Causeway,  near  Edinburgh,  etc. ;  in  N.  Scotia  at 
C.  Blomidon. 

Pxeudonatrolite.    Resembles  natrolite;  fuses  less  easily.    Elba,  in 
granite. 
21 


322  DESCRIPTIONS   OF   MINERALS. 

Analcite. 

Isometric.    Usually  in  trapezohedrons  (Fig.  1,  also  Fig.  2). 

The  appearance  some- 
times seen  in  polarized  light 
is  shown  in  Fig.  14,  page  79. 
Often  colorless  and  trans- 
parent; also  milk-white, 
grayish  and  reddish  white, 
and  som  etimes  opaque.  Lus- 
tre vitreous.  H.  =  5-5*5. 
G.  =  2-25. 

Composition.  Na2A1012Si4  -f-  2  aq  =  Silica 54*47,  alumina 
23-29,  soda  14*07,  water  8-17  =  100.  B.B.  fuses  easily  to  a 
colorless  glass.  Decomposed  by  hydrochloric  acid ;  the 
silica  separates  in  gelatinous  lumps. 

Diff.  Characterized  by  its  crystallization,  and  absence  of 
cleavage.  Distinguished  from  quartz  and  leucite  by  giving 
water  in  a  closed  glass  tube;  from  calcite  by  its  fusibility, 
and  by  not  effervescing  with  acids;  from  chabazite  and  its 
varieties  by  fusing  without  intumescence  to  a  glassy  globule, 
and  by  the  crystalline  form. 

Obs.  Found  in  cavities  and  seams  in  amygdaloidal  trap, 
basalt  and  other  eruptive  rocks,  and  sometimes  in  granite, 
syenyte,  and  gneiss. 

Occurs  in  fine  crystallizations  in  Nova  Scotia;  also  at 
Bergen  Hill,  N".  J.;  Perry,  Me.;  in  the  trap  of  the  Cop- 
per region,  Lake  Superior ;  and  near  Montreal,  Canada. 
The  Faroe  Islands;  Iceland;  Glen  Farg,  near  Edinburgh  ; 
Kilmalcolm,  the  Campsie  Hills,  and  Antrim;  the  Vicen- 
tine;  the  Hartz  at  Andreasberg;  Sicily,  and  Vesuvius. 

The  name  analcite  is  from  the  Greek,  analJcis,  weak,  al- 
luding to  its  weak  electric  power  when  heated  or  rubbed. 

JSudnophite.     Near  analcite.     Norway. 

Faujasite.    In  isometric  octahedrons.     The  Kaiserstuhl,  Baden. 

Chabazite. 

Ehombohedral;  R  :  R  =  94°  46'.  Often  in  rhombohed- 
rons,  much  resembling  cubes;  also  in  complex 
twins.  Cleavage  parallel  to  R.  Never  mssivae  or 
fibrous. 

Color  white;  yellowish;  flesh-red  or  red  (A cadi- 
alite).     Lustre  vitreous.     Transparent  to  trans- 
lucent.    H.  =  4-5.     G.  =  2-08-2-19. 


HYDROUS   SILICATES — ZEOLITE   SECTION.  323 

Composition.  CaAlO^Si,  -j-  6  aq,  with  a  little  Na2  or  K3 
in  place  of  part  of  the  Ca.  The  Nova  Scotia  acadialite 
afforded  Silica  52-20,  alumina  18*27,  lime  6 -58,  soda  and 
potash  2 '12,  water  20 '52.  B.B.  intumesces  and  fuses  to  a 
nearly  opaque  bead.  Decomposed  by  hydrochloric  acid, 
with  the  separation  of  slimy  silica.  In  the  closed  tube 
gives  water.  Phacolite  is  a  variety  in  complex  glassy 
crystals. 

Diff.  The  nearly  cubical  form  often  presented  by  the 
crystals  of  chabazite  is  a  striking  character.  It  is  distin- 
guished from  analcite  as  stated  under  that  species ;  from 
calcitc  by  its  hardness  and  action  with  acids;  from  fluorite 
by  its  form  and  cleavage,  and  its  showing  no  phosphores- 
cence. 

Ob 8.  Found  in  trap  and  occasionally  in  gneiss,  syenyte, 
and  other  rocks.  From  the  Faroe  Ids. ;  Giant's  Causeway, 
Antrim;  Isle  of  Skye;  Bohemia  (Phacoliie)',  Poonah  in 
India.  The  trap  of  Connecticut  Valley,  but  in  poor  speci- 
mens; at  Hadlyme  and  Stonington,  Conn.;  Charlestown, 
Mass.;  Bergen  Hill,  N.  J.;  Piermont,  N.  Y.;  Jones's  Falls, 
near  Baltimore  (Haydenite)',  fine  in  Nova  Scotia,  both 
white  crystals,  and  also  red  (Acadialite)  in  abundance. 

ITersehelite.  Near  chabazite  in  form  ;  formula(i]Sra23Ca)AlO13Si4  -f- 
6  aq.  Richmond,  in  Victoria,  Australia;  Sicily. 

Gmelinite.  Closely  resembles  some  chabazite,  but  its  crystals  are 
usually  hexagonal  rather  than  rhombohedral  in  appearance  ;  formula 
(N,i2,  Ca)AlOi2Si4;  a  Bergen  Hill  specimen  afforded  Silica  48'67,  alu- 
mina 18-72,  lime  2'60,  soda  9'14,  water  21 '35  =  100'48;  gelatinizes 
with  hydrochloric  acid,  but  in  other  respects  resembles  chabazite. 
Andreasberg;  Antrim,  Ireland;  Skye;  Bergen  Hill,  N.  J.;  Nova 
Scotia,  at  Cape  Blomidon  (Ledererite).  Named  after  the  chemist 
Gmelin.  Qroddeckite  is  a  variety. 

J^evynite  (Levyne).  Rhombohedral,  somewhat  resembling  gmclin- 
ite  in  its  crystals;  the  water  excluded,  having  the  quantivalent  ratio  of 
labradorite,  1:3:6;  colorless,  white,  grayish,  reddish.  Iceland ; 
Greenland;  Antrim;  Londonderry;  Hartfield  Moss  near  Glasgow. 
Named  after  the  crystallographer,  Levy. 

Harmotome. 

Monoclinic.  Unknown  except  in  compound  crystals;  and 
commonly  in  forms  similar  to  the  annexed  figure;  also  in 
compound  rhombic  prisms. 

Color  white;  sometimes  gray,  yellow,  red,  or  brownish. 
Subtransparent  to  translucent.  Lustre  vitreous.  H.  =  4'5. 
Q.  =245. 


324 


DESCRIPTIONS   OF  MINERALS. 


Composition.  BaA1014Si&  -f-  5  aq  =  Silica  46*5,  alumina 
15-9,  baryta  23 -7,  water  13-9  =  100;  but  a  little  of  the 
baryta  replaced  by  potash.  B.B.  whitens,  crumbles,  and 
fuses  quietly  to  a  white  translucent  glass.  Gives  water  in 
a  closed  glass  tube.  Partially  decomposed  by  hydrochloric 
acid,  and  if  sulphuric  acid  be  added  to  the 
solution,  a  heavy  white  precipitate  of 
barium  sulphate  is  formed.  Some  varie- 
ties phosphoresce  when  heated. 

Diff.  Its  twin  crystals,  when  distinct, 
cannot  be  mistaken  for  any  other  species 
except  phillipsite.  Much  more  fusible 
than  glassy  feldspar  or  scapolite;  does  not 
gelatinize  like  thomsonite. 

Obs.  In  amygdaloidal  trap,  and  in 
trachyte  and  phonolyte;  also  in  gneiss,  and  metalliferous 
veins.  Fine  at  Strontian  in  Scotland  (MorvenUe),  and  in 
Dumbartonshire;  Andreasberg  in  the  Hartz;  Kongsberg  in 
Norway.  Has  been  found  in  seams  in  the  gneiss  in  the 
upper  part  of  New  York  Island. 

Named  harmotome  from  the  Greek  Jiarmos,  a  joint,  and 
temno,  I  cleave. 

Phillipsite.  Near  harmotome  in  its  cruciform  crystals  and  other 
characters,  but  differing  in  containing  lime  in  place  of  baryta;  differs 
also  in  gelatinizing  with  acids  and  in  fusing  with  some  intumescence; 
also  occurs  in  sheaf -like  aggregations  and  in  radiated  crystallizations. 
The  Giant's  Causeway;  Capo  di  Bove;  Vesuvius;  Sicily;  Iceland. 

Brammte.  Hydrous  silicate  of  aluminium,  potassium,  magnesium 
and  iron.  Coal  shales  of  Noyant,  France. 

Stilbite. 

.  Monoclinic.  In  prisms  like  the  figure,  flattened  parallel 
to  the  face  i-i,  which  is  the  direction  of  cleavage; 
1  A  1  =  119°  16',  and  114°.  Also  in  sheaf-like 
aggregations,  and  spheres,  thin  pearly  lamellar- 
columnar  in  structure;  also  in  radiated  crystal- 
lizations; never  fine  fibrous. 

Color  white;  sometimes  yellow,  brown,  or  red. 
Subtransparent   to  translucent.     Lustre   highly 

pearly  on  cleavage  surface.     H.  =  3*5-4.     G.  =  2  '1-2  -15. 
Composition.    CaA1016Si6-l-  6  aq  =  Silica  57 '4,  alumina 

16-5,  lime  8-9,  water  17'2  =  100;  but  with  a  little  Na2  or  K3 

in  place  of  part  of  the  Ca.     B.  B.  exfoliates,  swells  up,  and 


HYDROUS   SILICATES — ZEOLITE   SECTION.  325 

curves  into  fan-like  forms,  and  fuses  to  a  white  enamel. 
Decomposed  by  hydrochloric  acid  without  gelatinizing, 

Diff.  Cannot  be  scratched  with  the  thumb-nail,  like  gyp- 
sum. Unlike  heulandite  in  its  crystals. 

Ops.  Occurs  mostly  in  trap  or  basaltic  rocks;  also  on 
gneiss  and  granite.  Found  on  the  Faroe  Ids.  ;  Isle  of  Skye ; 
Isle  of  Arran,  and  elsewhere,  Scotland ;  Andreasberg,  Hartz ; 
the  Vendayah  Mts.,  Hindostan.  Found  sparingly  at  the 
Chester  and  Charlestown  syenyte  quarries,  Mass.  ;  at  New 
Haven,  Thatchersville  and  Hadlyme,  Ct.,  and  other  points 
in  the  Connecticut  Valley  trap ;  at  Phillipstown,  N.  Y. ; 
Bergen  Hill,  N.  J.  f  in  the  copper  region  of  Lake  Superior; 
in  beautiful  crystallizations  at  various  points  in  Nova  Scotia. 

The  variety  in  spheres  (spherostilbite)  occurs  in  I.  Skye; 
Elba ;  in  the  U.  States,  in  Tyringham,  Mass. ;  in  N.  Scotia. 

Named  stilbite  from  the  Greek  stilbe  lustre.  Has  also 
been  called  Desmine,  and  in  Germany  Heulandite,  where 
heulandite  has  been  called  stilbite. 

Foresite.    From  Elba,  in  minute  crystals  on  tourmaline. 
Heulandite. 

Monoclinic.     In  right  rhomboidal  prisms  like  the  figure, 
with  perfect  pearly  cleavage  parallel  to  P,  and  other 
planes  vitreous  in  lustre.    P  AM  or  T  =  90°  ;  M  AT 
=129°  40'.     Color  white  ;   sometimes  reddish,  gray, 
brown.    Transparent  to  subtranslucent.    Folia  brit- 
tle.    H.  =  3-5-4.     G.  =  2'2. 

Composition.  CaA1016Si6-|-5  aq  =  Silica  59 •!,  alu- 
mina 16-9,  lime  9'22,  water  14'8  =  100.  Contains 
1  to  2  per  cent,  of  Na2  or  K2  in  place  of  part  of  the 
Ca.  Blowpipe  characters  like  those  of  stilbite.  In- 
tumesces  and  fuses,  and  becomes  phosphorescent.  Dis- 
solves in  acid  without  gelatinizing. 

Diff.  The  very  pearly  lustre  of  the  cleavage  face  is  a 
marked  characteristic.  Distinguished  from  gypsum  by  its 
hardness ;  from  apophyllite  and  stilbite  by  its  crystals ;  and 
from  the  latter  species  also  in  not  occurring  in  radiated, 
sheaf-like  or  spherical  crystallizations. 

Obs.  Found  in  cavities  and  fissures  in  trap ;  occasionally 
in  gneiss,  and  in  some  metalliferous  veins ;  in  large  crystal- 
lizations at  Berufiord,  Iceland ;  and  Vendayah  Mts. ,  Hin- 
dostan ;  also  at  Isle  Skye ;  near  Glasgow ;  Fassa  Valley ; 


326  DESCRIPTIONS   OF   MINERALS. 

Elba  (Oryzile);  at  Bergen  Hill,  N.  J.,  in  trap;  at  Had- 
lyme,  Ot.,  and  Chester,  Mass.,  on  gneiss;  Leiperville,  Pa.  ; 
near  Baltimore,  on  hornblende  schist  (Beaumont  it  e)\  at 
Peter's  Point  and  Cape  Blomidon,  and  other  places  in  Nova 
Scotia,  in  trap. 

Named  by  Brooke  after  Mr.  Heuland,  of  London. 

Brewsterite.  Crystals  monoclinic,  with  a  perfect  pearly  cleavage 
like  heulandite  ;  but  MAT  =  93°  40'  ;  H.=  4^-5  ;  G.=  2 '45  ;  for- 
mula analogous  to  that  of  heulandite,  but  baryta  and  strontia  take 
the  place  of  the  lime  and  soda.  Strontian,  Argyleshire ;  Antrim  ; 
Mont  Blanc  ;  near  Bareges,  Pyrenees. 

Epistilbite,  Composition  like  that  of  heulandite,  but  occurs  in  short 
and  very  obtuse  monoclinic  rhombic  prisms  (J*/\I=  135°  10').  Skye; 
the  Faroe  Ids. ;  Iceland  ;  Poonah,  India  ;  Margaretville,  Nova  Scotia. 
Parastilbite  and  Reusite  are  referred  here. 

Mordentte.  Fibrous  silky  concretions.  Morden,  Nova  Scotia. 
Steeleite  is  partially  altered  mordenite. 

III.  MARGAROPHYLLITE  SECTION. 
Talc. 

Orthorhombic ;  I/\I=  120°.  In  right  rhombic  or  hex- 
agonal prisms.  Usually  in  pearly  foliated  masses,  separat- 
ing easily  into  thin  translucent  pearly  folia.  Sometimes 
stellate,  or  divergent,  consisting  of  radiating  laminae.  Often 
massive,  consisting  of  minute  pearly  scales ;  also  crystalline 
granular ;  also  cryptocrystalline. 

Lustre  eminently  pearly,  and  feel  greasy.  Color  some 
shade  of  light  green  or  greenish  white ;  occasionally  silvery 
or  pearl  white ;  also  grayish  green  and  dark  olive-green. 
H.  =  1-1  *5  ;  easily  impressed  with  the  nail.  G.  =  2  '5—2  *8. 
Laminas  flexible,  but  not  elastic. 

VARIETIES.     Foliated  Talc.     White  to  greenish  white. 

Soapstone  or  Steatite.  White,  gray,  grayish  green; 
either  massive,  crystalline  granular,  or  impalpable ;  greasy 
to  the  touch.  French  chalk  is  a  milk-white  variety,  with 
a  pearly  lustre.  Potstone  or  Lapis  Ollaris  is  impure  soap- 
stone  of  grayish  green  and  dark  green  colors. 

Indurated  Talc.  A  slaty  talc,  of  compact  texture,  and 
above  the  usual  hardness,  owing  to  impurities. 

Rensselaerite.  A  compact  cryptocrystalline  rock,  from 
St.  Lawrence  and  Jefferson  cos.,  N.  Y.,  white,  yellow, 
grayish  white,  to  brown  and  black.  Has  sometimes  the 
form  and  cleavage  of  pyroxene,  and  is  in  part  at  least  a  prod- 


HYDROUS  SILICATES — MARGAROPHYLLITE   SECTION.    327 

uct  of  the  alteration  of  that  mineral.  Part  of  Pyrallolite 
belongs  here. 

Composition.  -JH2-jMg03Si  =  Silica  62*8,  magnesia  33 -5, 
water  3'7  =  100.  Usually  contains  a  little  iron  replacing 
magnesium.  B.B.  infusible;  after  moistening  with  cobalt 
nitrate  a  pink  tint;  in  closed  tube  gives  a  little  water,  but 
not  till  highly  heated.  Not  acted  upon  by  hydrochloric  acid. 

Diff.  The  extreme  softness,  greasy  feel,  foliated  struct- 
ure, when  crystallized,  and  pearly  lustre  of  talc  are  good 
characteristics.  Differs  from  mica  also  in  being  inelastic, 
although  flexible;  from  chlorite,  kaolinite,  and  serpentine 
in  yielding  little  water  wherTlieaTed  in  a  glass  tube.  Only 
the  massive  varieties  resemble  the  last-mentioned  species, 
and  chlorite  has  a  dark  olive-green  color.  Pyrophyllite, 
which  cannot  be  distinguished,  in  some  of  its  varieties,  by 
the  eye  alone,  from  talc,  becomes  dark  blue  when  moistened 
with  cobalt  nitrate  and  ignited. 

Obs.  Occurs  in  Cornwall,  near  Lizard  Point;  at  Portsoy 
in  Scotland;  at  Croky  Head,  Ireland;  in  the  Greiner 
Mountain,  Saltzburg.  Handsome  foliated  talc  occurs  at 
Bridge  water,  Vt. ;  Smithfield,  R.  I.;  Dexter,  Me.;  Lock- 
wood,  Newton,  and  Sparta,  N.  J.,  and  Amity,  N.  Y. ; 
Staten  Island,  near  the  Quarantine,  both  the  common  and 
indurated;  at  Cooptown,  Md.,  green,  blue,  and  rose-colored; 
in  Georgia.  Steatite  or  soapstone  is  abundant,  and  is 
quarried  at  Grafton,  Cambridgeport,  Chester,  Perkinsville, 
Saxton's  River,  Vt. ;  at  Francestown,  Orf ord,  Weare,  War- 
ner, Richmond,  Haverhill,  N.  H.;  at  Middlefield,  Mass.; 
in  Loudon  Co.,  Va.,  and  at  many  other  places. 

Talc  is  ground  up  and  used  largely  for  adulterating  soap, 
and  to  some  extent  in  the  manufacture  of  paper. 

Soapstone  is  sawn  into  slabs  and  used  for  linings  of  fur- 
naces, stoves  and  fire-places,  etc.;  made  into  images  in 
China,  and  into  inkstands  and  other  forms  in  other  coun- 
tries; ground  up  for  use  in  lubricating  machinery,  and  the 
inside  of  a  tight  boot;  worked  into  vessels  for  culinary  pur- 
poses in  Lombardy.  Soapstone  is  also  used  in  the  manu- 
facture of  porcelain;  it  makes  the  biscuit  semi-transparent, 
but  brittle  and  apt  to  break  with  slight  changes  of  heat.  It 
forms  a  polishing  material  for  serpentine,  alabaster,  and 
glass. 


328  DESCRIPTIONS   OF  MINERALS. 

Pyrophyllite. — Agalmatolite,  in  part. 

Near  talc  in  crystallization,  cleavage,  its  occurrence  in 
both  thin  foliated  and  fine-grained  massive  forms,  its  greasy 
feel,  its  white  to  pale  green  colors,  varying  to  yellowish,  its 
feeble  degree  of  hardness  (1-2).  The  folia  are  sometimes 
radiated.  G.  =  2  '75-2  -92. 

Composition.  An  aluminous  bisilicate,  instead  of  a  mag- 
nesian,  mostly  of  the  formiila,  A109Si3.  The  Chesterfield, 
S.  0.,  mineral  afforded  Genth,  Silica  64*82,  alumina  24-48,, 
iron  sesquioxide  0'96,  magnesia  0'33,  lime  0'55,  water  5*25 
=  100 '3 9.  B.B.  whitens  and  fuses  with  difficulty  on  the 
edges;  a  deep  blue  color  with  cobalt  solution;  yields  water 
in  the  closed  tube.  Radiated  varieties  exfoliate  in  fan-like 
forms. 

Obs.  Compact  pyrophyllite  is  the  chief  constituent  of  a 
kind  of  slate  or  schist,  which  has  been  used  for  slate  pen- 
cils, and  hence  is  called  pencil-stone.  Occurs  in  the  U'rals; 
at  Westana  in  Sweden;  in  Elfdalen,  with  cyanite;  foliated, 
in  N".  Carolina,  in  Cottonstone  Mountain ;  Chesterfield 
District,  S.  C.,  with  lazulite  and  cyanite;  Lincoln  Co.,  Ga., 
on  Graves  Mountain;  near  Little  Rock,  Ark.;  compact 
slaty  in  the  Deep  River  region,  N.  C.,  and  at  Carbonton, 
Moore  County,  N.  C. 

Sepiolite.— Meerschaum  of  the  Germans. 

Usually  compact,  of  a  fine  earthy  texture,  with  a  smooth 
feel,  and  white  or  whitish  color;  also  fibrous,  white  to  bluish 
green  in  color.  H.  =  2-2 '5.  The  earthy  variety  floats  on 
water. 

Composition.  ^H2fMg03Si  -f- 1|  aq  =  Silica  60 -8,  magnesia 
27 •!,  water  12-1  =  100.  B.B.  infusible,  or  fuses  with  great 
difficulty  on  the  thin  edges.  Much  water  in  a  closed  tube. 
A  pink  color  with  cobalt  solution. 

Occurs  in  Asia  Minor  in  masses  in  stratified  earthy  de- 
posits, and  extensively  used  for  pipe-bowls;  also  found  in 
Greece,  Moravia,  Spain,  etc. ;  also  in  fibrous  seams  at  a  sil- 
ver mine  in  Utah. 

Aphrodite.  Similar  to  the  preceding.  MgO3Si  +  f  H.  From  Swe- 
den. 

Gimolite.  A  clay  from  the  Island  of  Argentiera,  Kimole  of  the  Greeks: 
Richmond,  K  8.  W. 

Smectite.  A  kind  of  * '  Fuller's  Earth,"  a  name  given  to  unctuous  clays 
used  in  fulling  cloth. 


HYDROUS   SILICATES — MARGAKOPHYLLITE   SECTION.     329 

Montmorillonite.  Rose-red  to  white,  bluish;  soft  and  tender;  a  hy- 
drous aluminium  silicate.  Montmorillon,  France;  Cornwall;  Branch- 
ville,  Ct.  Stolpenite,  Confolensite,  Delanouite,  Steargillite,  the  8apo- 
liite  of  Plombieres,  are  related  to  this  species. 

Glauconite.— Green  Earth. 

In  dark  olive-green  to  yellowish  green  grains,  or  granular 
masses,  with  dull  lustre.  H.  =2.  G.  =  2*2-2-4. 

Composition.  Essentially  a  silicate  of  iron  and  potassium. 
Formula  RR012Si4  -f-  3  aq,  in  which  R  is  mainly  Fe  and  K2, 
and  R  is  Al,  but  sometimes  largely  Fe.  Analyses  give 
mostly  50-58  per  cent,  silica,  20-24?  iron  protoxide,  4-12  of 
potash,  and  8-12  of  water.  B.B.  fuses  easily  to  a  mag- 
netic glass.  Yields  water  in  a  closed  tube. 

Obs.  Mixed  with  more  or  less  sand,  it  forms  thick 
beds  called  "green  sand  "in  the  Cretaceous  formation,  and 
also  in  the  Lower  Tertiary;  also  occurs  in  other  older  rock 
formations  down  to  the  Lower  Silurian.  Found  also,  first 
by  Pourtales,  in  the  pores  of  corals  and  cavities  of  Rhizopod 
shells  over  the  existing  sea-bottom,  showing  it  to  be  a  ma- 
rine product,  and  one  now  in  progress  of  formation.  The 
grains  of  the  Cretaceous,  Tertiary,  and  Lower  Silurian  beds 
were  shown  first  by  Ehrenberg  to  be  the  casts  of  the  inte- 
rior of  shells  of  Rhizopods.  The  silica  has  been  supposed 
to  come  from  the  siliceous  secretions  of  a  minute  sponge 
growing  in  the  cavities  that  afterward  became  occupied  by 
the  glauconite.  Abundant  in  New  Jersey  a  few  miles  north, 
east  and  south  of  Freehold. 

Bravamte.  Gray  to  greenish;  H.  =  1-2;  feel  greasy.  Near  glau- 
conite. 

Celadonite.  A  green  earth  with  53  per  cent,  of  silica,  from  amygda- 
loid, near  Verona;  Scotland.  Probably  an  impure  chlorite. 

Chloropal.  Massive;  somewhat  opal-like  in  appearance;  greenish 
yellow  to  pistachio  green;  consists  chiefly  of  silica,  iron  sesquioxide, 
and  water.  Nontronite,  Pinguite,  TTnghwarite,  and  Gramenite  are 
varieties  of  it.  Unghwar,  Hungary;  Nontron,  France;  near  Gottingen; 
Bohemia;  Mudgee,  K  8.  W. 

Stilpnomelam.  Foliated  and  also  fibrous,  or  as  a  velvety  coating; 
black  to  brownish  and  yellowish  bronze  in  color  and  lustre;  G.  —  3- 
3*4;  chiefly  silica  and  iron  oxides,  with  8  to  9  per  cent,  of  water. 
Chalcodite,  in  velvety  coatings  at  the  Sterling  Iron  Mine,  Antwerp, 
Jefferson  Co.,  N.  Y.,  is  here  included. 

Serpentine. 

Usually  massive  and  compact  in  texture;  also  lamellar  or 
foliated,  the  folia  brittle;  also  columnar,  asbestiform,  and 


330  DESCRIPTIONS   OF   MINERALS. 

delicately  silky  fibrous.  Often  in  crystals  pseudomorphous 
after  chrysolite  and  some  other  species.  Color  light  to  dark 
oil-green,  to  olive-green  and  blackish  green;  also  greenish 
yellow,  brownish  yellow,  brownish  red;  rarely  white.  Lus- 
tre weak;  resinous,  inclining  to  greasy.  Translucent  to 
nearly  opaque.  H.  =  2 -5-4.  GL  =  2 -5-2 '6.  Feel,  espe- 
cially of  powder,  a  little  greasy.  Tough.  Fracture  con- 
choidal. 

Composition.  A  hydrous  magnesium  silicate,  like  talc,  but 
containing  more  water  and  less  silica.  H2Mg308Si2  + 1  aq  = 
Silica  43-48,  magnesia.  43'48,  water  13-04=  100.  B.B. 
fuses  with  much  difficulty  on  thin  edges.  Yields  water  in 
the  closed  tube.  Decomposed  by  hydrochloric  acid,  leaving 
a  residue  of  silica.  In  some  kinds  iron  replaces  part  of  the 
magnesium. 

Specimens  of  a  rich  oil-green  color,  and  translucent,  are 
called  precious  serpentine,  and  the  nearly  opaque  kinds 
common  serpentine.  Chrysotile  is  fibrous  serpentine;  it  in- 
cludes Amianthus  and  part  of  Asbestufi.  Unlike  true  as- 
bestus,  it  affords  much  water  in  a  closed  tube.  Metaxite, 
Picrolite,  and  Baltimorife  are  coarse  fibrous  kinds.  A  thin 
foliated  variety,  from  Hoboken,  N".  J.,  was  named  Marmo- 
lite,  before  it  was  known  to  be  serpentine;  Antigorite  and 
Wiliiamsite  are  coarse  foliated  varieties;  RefdansJcite  con- 
tains nickel.  A  porcelain-like  serpentine — the  Meerschaum 
of  Taberg  and  Sala — has  been  called  Porcellophite  ;  and  a 
resin-like  variety,  Retinalite  and  Vorhauserite.  Mixed  with 
limestone  it  makes  a  green  clouded  marble  called  Verd-an- 
tique  and  OpMolite, 

Diff.  The  distinguishing  characters  of  the_cjompaet min^ 
era!  are  no  cleavage,  feeble  lustre,  slightly  waxy  or  oily  lus- 
tre, little  hardness,  being  so  soft  as  to  be  easily  cut  with  a 
knife,  yielding  much  water,  and  specific  gravity  not  over 
2-65. 

Qbs.  Named  from  its  screen  color,  which  is  often  clouded, 
serpent-like.  Common  as  a  rock  as  well  as  an  imbedded 
mineral.  It  has  been  made  through  the  alteration  of  an- 
hydrous magnesian  silicates,  as  chrysolite,  pyroxene,  ensta- 
tite,  hypersthene,  tremolite,  actinolite,  chlorite,  chondrodite, 
and  others.  Chrysolite  is  the  most  common  source.  Some 
basaltic  and  other  eruptive  rocks  consisting  largely  of  pyr- 
oxene and  chrysolite  have  been  changed  to  impure  serpen- 
tine. Foliated  chlorite  has  given  origin  to  some  foliated 


HYDKOUS  SILICATES — MAKGAROPHYLLITE  SECTION.    331 

serpentine,  as  probably  that  of  marmolite;  and  cleavable 
pyroxene  to  the  partially  altered  foliated  kinds  called  Bastite, 
Schiller-spar,  and  Antillite.  Pelhamite  is  an  asbestiform 
serpentine  material  made  by  alteration.  The  white  marble 
of  Essex  Co.,  N.  Y.,  dotted  with  green  serpentine,  a  "  verd- 
antique,"  was  once  dotted  probably  with  pyroxene;  and 
other  verd-antiques  have  had  a  similar  origin.  The  serpen- 
tine of  New  Rochelle,  NY  Y.,  was  made  in  part  from  ensta- 
tite  and  tremolite  or  actinolite;  and  that  of  Brewster,  N.  Y., 
part  of  which  is  white,  from  chondrodite,  chlorite,  enstatite, 
and  to  a  small  extent  from  biotite  and  dolomite.  The 
"Eozoon,"  consisting  of  delicate  layers  of  serpentine  and 
calcite,  is  regarded  by  some  as  serpentine  of  mineral  origin, 
which  became  cracked  from  drying  while  it  was  in  a  semi-. 

felatinous  state,  and  which  then  had  the  delicate  cracks 
lied  by  calcite. 

Serpentine  occurs  in  Cornwall;  near  Portsoy  in  Aberdeen- 
shire;  in  Corsica,  Siberia,  Saxony,  Norway,  Silesia,  etc. 

In  the  United  States  it  occurs  at  Phillipstown,  Port 
Henry,  Gouverneur,  Warwick,  New  Rochelle,  Eye,  Staten 
Island,  N.  Y. ;  Newburyport,  Westfield,  Blandf  ord,  Mass. ; 
Kelly  vale,  New  Fane,  Vt.;  Deer  Isle,  Me.;  New  Haven, 
Ct.;  Bare  Hills,  Md.;  Hoboken,  N.  J.;  Brewster's,  Put- 
nam Co.,  N.  Y.;  Texas  and  elsewhere,  Pa.;  in  N.  Carolina; 
over  large  areas  N!  and  S.  of  San  Francisco,  Cal. ;  Canada, 
at  Orford,  Ham,  Bolton,  etc. 

Serpentine  when  polished  has  much  beauty,  especially 
when  constituting  a  verd-antique  marble.  Chromic  iron 
or  magnetite  is  usually  disseminated  through  it,  and  in- 
creases the  variety  of  its  colors.  It  occurs  near  Milford 
and  New  Haven,  Ct.;  Port  Henry,  Essex  Co.,  N.  Y.,  and 
elsewhere.  Pennsylvania  serpentine  is  used  as  a  building- 
stone  in  Philadelphia. 

The  asbestus  of  this  species  is  used  like  hornblende  as- 
bestus,  and  largely  obtained  for  the  trade  at  Staten  Island, 
in  Canada,  and  in  Italy.  But  it  is  an  inferior  kind,  owing 
to  the  14  pounds  of  water  present  to  every  hundred  of  the 
pure  material,  which  a  high  heat  will  drive  off  and,  if  it  is 
confined,  may  do  it  explosively. 

Boweniie.  Has  the  composition  of  serpentine,  but  the  hardness 
6-5-6,  and  the  aspect  of  nephrite,  with  G.  =  2  '59-2 '8.  Smithfield,  R.  I. 


332  DESCRIPTIONS   OP  MINERALS. 

Deweylite. 

Massive.  Color  whitish,  yellowish,  brownish  yellow, 
greenish,  reddish.  Has  the  aspect  of  gum-arabic  or  a 
resin.  Very  brittle.  H.  =  2-3  '5.  G.  =  1  '9-2  '25. 

Composition.  Near  serpentine,  but  containing  20  per 
cent,  of  water. 

Obs.  From  Middlefield,  Mass.;  Bare  Hills,  Md.  (Gym- 
nite);  Texas,  Pa.;  the  Fleims  Valley,  Tyrol. 

Cerolite.  Related  to  deweylite  ;  from  Silesia.  Limbachite  from 
Limbach,  and  Zobliteite  from  Zoblitz,  are  similar. 

Hydrophite.  Like  deweylite,  but  containing  iron  in  place  of  part 
of  the  magnesium.  Taberg  in  Smaoland. 

Jenkinsite  is  a  fibrous  variety  of  bydrophite  occurring  on  mag- 
netite at  O  'Neil's  mine,  in  Orange  Co.,  N.  Y. 

Oenthite  or  Nickel-gymnite.  Similar  to  deweylite,  but  containing 
much  nickel  ;  analysis  affording  Silica  35  '36,  nickel  protoxide  30  '64, 
iron  protoxide  0'24,  magnesia  14'60,  lime  0  26,  water  19'09  =  100'19  ; 
G  -  2;4.  Texas,  Pa.;  Webster,  N.  C.;  Michipicoten  Island,  Lake 
Superior;  Malaga,  Spain;  Saasthal,  Upper  Valois.  Rottmte  is 
similar. 

Saponite. 

Soft,  clay-like,  of  the  consistence,  before  drying,  of 
cheese  or  butter,  but  brittle  when  dry.  Color  white,  yel- 
lowish, grayish  green,  bluish,  reddish.  Does  not  adhere 
to  the  tongue. 

Composition.  A  hydrous  silicate  of  magnesia  containing 
some  alumina. 

From  Lizard's  Point,  Cornwall,  in  serpentine.  Also 
from  geodes  of  datolite,  Eoaring  Brook,  Ct.  ;  in  trap,  north 
shore  of  Lake  Superior. 

Kaolinite. 

Orthorhombic;  /A/  =120°.  Massive,  clay-like,  but 
consisting  often  of  thin,  microscopic,  rhombic  or  hexagonal 
crystals;  either  compact,  friable,  or  mealy.  Feels  greasy. 
Color  white,  grayish  white,  yellowish,  sometimes  brownish, 
bluish,  or  reddish.  Scales  flexible,  inelastic.  H.  —  1-2  *5. 


Composition.  H2A108Si2  -f-  1  aq  =  Silica  46*4,  alumina 
39  -7,  water  13  -9  =  100.  The  similarity  of  the  composition 
to  that  of  serpentine  will  be  seen  on  comparing  the  two 
formulas.  B.  B.  infusible.  A  blue  color  with  cobalt  solution. 
Yields  water  in  the  closed  tube.  Insoluble  in  acids. 


HYDROUS   SILICATES — MARGAROPHYLLITE   SECTION.    333 

OJ)s.  The  soapy  feel  of  kaolinite  distinguishes  a  clay  con- 
sisting of  it  or  containing  much  of  it;  when  common  clays  are 
"  unctuous"  it  is  usually  owing  to  the  presence  of  kaolinite. 
Kaolinite  has  been  made  through  the  decomposition  of 
aluminous  minerals,  and  especially  feldspars,  but  mostly 
from  the  potash  feldspar,  orthoclase.  In  the  case  of  these 
feldspars  the  process  (1)  removes  the  alkalies;  (2)  leaves 
the  alumina,  or  a  large  part  of  it,  and  part  of  the  silica; 
and  (3)  adds  water.  So  that  orthoclase,  K2A10)6Si6  loses 
K2  and  part  of  the  Si  and  0,  and  becomes  changed  to  H2A1O8 
Si2  + 1  aq;  half  the  water  which  is  added  replaces  K2  which 
is  removed.  Many  granites,  gneisses,  and  feldspar-bearing 
quartzytes  undergo  rapidly  this  change,  so  that  extensive 
beds  of  kaolinite  have  been  formed  and  are  now  making  in 
many  regions.  This  result  is  promoted  by  the  action  of 
the  carbonic  acid  of  rain  and  other  waters,  which  removes 
'the  alkali;  also  by  that  of  the  organic  acids  which  the  de- 
composition of  plants  or  animals  contribute  to  such  waters. 
The  kaolinite  is  usually  washed  out  by  flowing  waters  from 
the  decomposed  material  to  make  the  large  pure  deposits. 
The  New  Jersey  clay-beds  of  the  Cretaceous  formation  and 
those  of  Long  Island,  N.  Y.,  are  mainly  kaolinite.  .  A  pure 
kaolinite  bed  occurs  at  Brandon,  Vt.,  along  with  a  limo- 
nite  bed;  a  much  larger  at  Clayton  in  New  Marlboro',  Mass. ; 
also  in  Delaware  and  Chester  cos.,  Pa.;  at  King's  Mtn., 
S.  C. ;  also  in  other  States.  Most  of  the  limonite  beds  of 
Eastern  N.  America  afford  some  kaolinite;  yet  it  is  gen- 
erally more  or  less  colored  by  iron  oxide. 

Common  clays  consist  of  powdered  feldspar,  quartz,  and 
other  mineral  material,  with  more  or  less  kaolinite.  They 
burn  red  in  case  they  contain  iron  in  the  state  ordinarily 
present  in  them  of  iron  carbonate,  or  hydrous  iron  oxide 
(limonite),  or  in  combination  with  an  organic  acid,  or  in 
some  other  alterable  state  of  composition,  heat  driving  off 
the  carbonic  acid  or  water,  or  destroying  the  organic  acid, 
and  so  leaving  the  red  oxide  of  iron  (or  sesquioxide),  or 
favoring  its  production.  But  the  iron  may  be  so  combined 
as  not  to  give  the  red  .color;  and  this  has  been  found  to  be 
true  with  the  clays  from  which  the  cream-colored  Milwau- 
kee (Wisconsin)  brick  are  made,  and  that  of  other  clay 
beds  in  that  vicinity.  The  iron  may  be  there  in  the  state 
of  the  silicate,  zoisite;  or  it  may  form  this  mineral,  or  one 
allied  to  it,  in  the  kiln.  When  clay  consists  in  part  of 


334  DESCRIPTIONS   OF   MINERALS. 

powdered  feldspar,  it  is  more  or  less  fusible  and  unfit  for 
making  fire-bricks. 

Pure  kaolinite  (or  kaolin  as  it  is  ordinarily  called)  is 
used  in  making  the  finest  porcelain.  For  this  purpose  it  is 
mixed  with  pulverized  feldspar  and  quartz,  in  the  propor- 
tion needed  to  give,  on  baking,  that  slight  incipient  degree 
of  fusion  which  renders  porcelain  translucent.  The  name 
kaolin  is  a  corruption  of  the  Chinese  word  Raiding,  mean- 
ing high  ridge,  the  name  of  a  hill  near  Jauchau-Fu,  where 
the  mineral  is  obtained;  and  the  petuntze  (peh-tun-tsz)  of 
the  Chinese,  with  which  the  kaolin  is  mixed  in  China  for 
the  manufacture  of  porcelain,  is,  according  to  S.  W.  Wil- 
liams, a  quartzose  feldspathic  rock,  consisting  largely  of 
quartz.  The  word  porcelain  was  first  given  to  China-ware 
by  the  Portuguese,  from  its  resemblance  to  certain  sea- 
shells  called  Porcellana  ;  they  supposed  it  to  be  made  from 
shells,  fish-glue,  and  fish-scales  (S.  W.  Williams). 

The  white  clays  are  used  for  stoneware,  fire-bricks,  re- 
torts for  gas-works,  sewer-pipes,  etc. ;  and  the  pure  kaolin 
extensively  for  giving  body  and  weight  to  paper. 

Finite. 

Amorphous,  and  usually  cryptocrystalline ;  but  often 
having  the  form  of  the  crystals  of  other  minerals  from  the 
alteration  of  which  it  has  been  made.  Colors  grayish,  green- 
ish, brownish,  and  sometimes  reddish.  Lustre  feeble;  waxy. 
Translucent  to  opaque.  H.  =  2 '5-3  -5,  G.  =  2 '6-2*7; 
some,  2*85. 

Composition.  Mostly  (H3K)aAlapaoSiB.  The  pinite  of 
Saxony  afforded  Silica  4G-83,  alumina  27 '65,  iron  sesqui- 
oxide  8 '71,  magnesia  1-02,  lime  0*49,  soda  0'40,  potash 
6-52,  water  3*83  =  99-42;  and,  in  another  analysis,  potash 
10 '74.  It  has  in  part  the  physical  characters  of  serpentine; 
but,  at  fhe  same  time,  it  has  nearly  the  composition  of  a 
hydrous  potash  mica.  Some  of  it  has  been  proved  to  con- 
sist of  very  minute  scales  that  are  mica,  and  it  is  inferred 
that  pinite  may  usually  be  a  massive  form  of  hydrous  mus- 
covite. 

Obs.  The  varieties  are  in  general  pseudomorphs  after 
different  minerals,  and  hence  comes  a  part  of  their  varia- 
tions in  composition.  They  include  Pinite,  from  the 
Pini  Mine,  near  Schneeberg  and  elsewhere;  Gieseclcite, 
pseudomorph  after  nephelite  from  Greenland,  and  from 


HYDROMICA   GROUP.  335 

Diana,  N.  Y. ;  Killviite,  formed  from  spodumene,  at  Kil- 
liney  Bay,  Ireland,  Branchville,  Ct.,  and '  Chesterfield, 
Mass.;  Dysyntribite,  from  Diana,  N.  Y.,  identical  with 
gieseckite;  Pinitoid,  from  Saxony;  }Yihonite,  from  Bat h- 
urst,  Canada,  having  the  cleavage  of  scapolite;  Terenite, 
from  Antwerp,  N.  Y.,  like  Wilsonite;  Agalmatolite,  or 
Payoditc,  from  China,  being  one  of  the  materials  for  carv- 
ing into  images,  ornaments,  models  of  pagodas,  etc.;  Gi- 
gautolite  and  Iberite,  which  have  the  form  of  iolite.  A 
variety  from  Elba  was  formed  from  andalusite. 

Polyargite,  Rosite,  Cataspilite,  Biharite,  Grumbelite,  Rauite,  Restor- 
melite,  are  related  materials. 

Pholerite,  Halloysite,  Severite,  Glagerite,  Lenzinite,  Bole,  Litfumarge, 
are  names  of  clay-like  minerals. 

Palagonite.  The  material  of  some  tufas,  and  the  result  of  change 
through  the  agency  of  steam  or  hot  water  at  the  time,  probably,  of  the 
deposition  of  the  material ;  a  mixture,  and  not  a  true  mineral.  Tufas 
of  Iceland,  Sicily,  etc.  Named  from  Palagonia,  Sicily.  - 

HYDROMICA  GROUP. 

The  following  species  are  mica-like  in  cleavage  and  aspect, 
but  talc-like  in  wanting  elasticity,  in  greasy  feel,  and  in 
pearly  lustre.  They  are  sometimes  brittle.  Common  mica, 
muscovite,  readily  becomes  hydrated  on  exposure ;  but 
hydrous  micas  are  not  all  a  result  of  alteration.  Hydromica 
schists  form  extensive  rock-formations,  equal  to  those  of  the 
ordinary  mica-  schists.  They  were  for  the  most  part  called 
Talcose  slate  (or  T'alk-schiefer  in  German)  from  their  greasy 
feel,  until  the  fact  was  ascertained  that  they  contained  no 
magnesia : .  a  point  demonstrated  for  the  Taconic  slates  of 
the  western  border  of  Massachusetts,  by  C.  Dewey,  in  1819, 
and  later,  by  G.  F.  Barker,  for  those  of  Vermont. 

Margarodite.  Damourite,  Hydrous  micas  related  to  muscovite, 
which  see  (p.  288).  Parophite  is  a  hydromica  schist  from  Pownal, 
Vt. ,  and  Stanstead,  Canada.  Sericfte  and  sericite  schist  are  hydromica 
schist  from  near  Wiesbaden  and  elsewhere. 

Groppite.  A  rose-red  to  brownish  red  foliated  mineral  from  Gropp- 
torp,  Sweden. 

Euphyllite.  Mica-like;  folia  rather  brittle;  lustre  pearlv,  white  or 
colorless;  contains  much  sodium;  an  analysis  afforded  Silica  41 '6, 
alumina  42-3,  lime  1\5,  potash  3'2,  soda  5'9,  water  5'5  =  100.  Occurs 
with  corundum  at  Unionville,  Delaware  County,  Pa. 

Cookeite.  In  minute  mica  like  scales,  and  in  slender  six-sided 
prisms;  affords  only  2*57  of  potash,  with  2'82  of  lithia;  the  water 


336  DESCRIPTIONS  OF  MINERALS. 

13 '41  per  cent.  On  crystals  of  red  tourmaline,  at  Hebron  and  Paris, 
Me. ,  having  been  formed  through  their  alteration.  Named  after  Prof. 
J.  P.  Cooke,  of  Cambridge,  Mass. 

Voigtite.  The  mica  of  a  granite  at  Ehrenberg,  near  Ilmenau,  which 
has  the  composition  of  biotite,  plus  9  per  cent,  of  water. 

Roscoelite.  A  vanadium -mica  of  dark  brownish  green  color,  occur- 
ring in  micaceous  scales,  and  affording  over  20  per  cent,  of  vanadium 
oxides,  along  with  47'69  of  silica,  14  10  of  alumina,  7'59  of  potash, 
4'96  of  water,  and  a  little  magnesia  and  soda.  Probably  a  mixture. 
From  Granite  Creek  Gold  Mine,  El  Dorado  €ounty,  California. 

Fahlunite. 

In  six  and  twelve-sided  prisms,  usually  foliated  parallel 
to  the  base,  but  owing  the  prismatic  form  to  the  mineral 
from  which  it  was  derived.  Folia  soft  and  brittle,  of  a 
grayish  green  to  dark  olive-green  color,  and  pearly  lustre. 

Composition.  A  hydrous  silicate  of  aluminium  and  iron 
with  little  or  no  alkali,  and  in  this  last  point  differing  from 
pinite.  An  average  specimen  afforded  Silica  44-60,  alumina 
30 '10,  iron  protoxide  3 '86,  manganese  protoxide  2*24,  mag- 
nesia 6-75,  lime  1'35,  potash  1'98,  water  9'35  =  100-23. 
B.B.  fuses  to  a  white  glass.  In  a  closed  tube  gives  water. 
Insoluble  in  acids. 

Diff.  It  is  distinguished  from  talc  by  affording  much 
water  before  the  blowpipe,  and  readily  by  its  association 
with  iolite,  and  its  large  hexagonal  forms,  with  brittle  folia. 

Qbs.  Fahlunite  has  been  derived  from  the  alteration  of 
iolite.  The  quantivalent  ratio  of  iolite  for  the  protoxides, 
sesquioxides,  and  silica  is  1:3:5;  and  for  fahlunite,  the 
same,  with  1  for  the  water,  making  the  whole  1:3:5:1. 
The  hydration  appears  to  go  on  at  the  ordinary  temperature, 
and  in  some  localities  all  the  iolite  to  a  considerable  depth 
in  the  rock  is  changed  to  fahlunite.  There  are  different 
varieties,  depending  on  the  amount  of  water,  and  the  con- 
ditions under  which  the  change  has  taken  place.  The 
names  they  have  received  are  Hydrous  Iolite,  Clilorophyllite, 
Esmarkite,  Aspasiolite,  Pyrargillite,  Triclanfe.  Fahlunite 
was  so 'named  from  its  locality,  Fahlun,  Sweden;  and  Chlo- 
rophyll ite  from  its  greenish  color  and  foliated  structure,  the 
specimens  to  which  it  was  given  occurring  at  Unity,  N.  H. 
Haddam,  Ot.,  is  another  locality.  Gigantolite  and.  Iberite 
are  also  altered  iolite,  but  they  contain  potash,  and  belong 
hence  to  the  Pinite  Group. 


CHLOEITE   GROUP.  337 

Resembles  ottrelite  ;    lamellar  ;    grayish  black.      In 
analysis,  Silica  44'79,  alumina  29'71,  iron  protoxide  20'75,  magnesia 
0'62,  \vater4-93  =  lOO'SO;  oxygen  ratio  1  :  3  :  6  :  10.   From  Venasque, 
Pyrenees. 
JErinite.    A  bright  blue  earthy  mixture.    From  the  Pyrenees. 

CHLORITE  GROUP. 

The  chlorite  group  includes  the  hydrous  jSubsilicatcs  of 
the  Margarophyllite  Section  and  also  some  related  species 
that  are  Unisilicates.  The  proportion  of  sjlicajis  sm.%11?  the 
percentage  afforded  by  analyses  being  under  38,  and  mostly 
under  30.  The  minerals  when  well  crystallized  are  foliated 
like  the  micas,  and  have  the  plane  angle  of  the  base  of  the 
crystals  120°,  but  the  folia  are_inelastfc  and  in  some  species 
brittle.  They  also  occurTn'fibrousanSTn  fine  granular  and 
conmact^  forms,  and  the  latter  are  usually  most  common. 
Green,  varying  from  light  to  blackish  green,  is  the  prevail- 
ing color,  yet  gray,  yellowish,  reddish,  and  even  white  and 
black  also  occur;  and  the  colored  transparent  or  translu- 
cent are  dichroic.  The  green  color  is  owing  to  the  presence 
of  iron,  and  fails  only  in  species  containing  little  or  none 
of  it.  All  of  the  species  yield  water  in  a  closed  tube. 
The  quantivalent  (or  combining)  ratio  f or  R  -J-  R  and  Si  is, 
in  the 

Pyrosclerite  subdivision. 1:1. 

Chlorite  subdivision 1  >.  f ,  1  :  f,  1  :  £. 

Chloritoid  subdivision 1  :  \  to  1  :  \. 

The  chlorite  subdivision  includes  Penninite,  Eipidolite, 
and  Prochlorite,  together  with  some  related  dark  green  to 
blackish  green  species.  Some  species  of  this  subdivision 
characterize  extensive  rock-formations,  making  chlorite 
schist  or  slate;  and  they  give  rise  also  to  chloritic  varieties 
of  other  rocks.  Moreover,  chlorite  is  a  result  of  the  altera- 
tion of  pyroxene,  hornblende,  and  some  other  iron-bearing 
minerals ;  and  pyroxenic  igneous  rocks,  like  basalt,  are 
often  strongly  chloritic  (as  revealed  by  the  microscopic 
examination  of  thin  transparent  slices),  in  consequence  of 
this  alteration — but  alteration  that  took  place  before  the 
rock  had  cooled.  Such  green  chloritic  material,  where  the 
species  is  not  determinable,  has  been  called  Viridite.  The 
cavities  in  amygdaloid  are  often  lined,  and  sometimes  filled, 
by  a  species  of  chlorite,  which  was  made  from  certain  con- 
22 


338  DESCEipTioisrs  OF  MINERALS. 

stituents  of  the  amygdaloid  in  the  manner  just  stated;  and 
the  rocks  adjoining  trap-dikes  are  at  times  penetrated  by 
chlorite  made  in  them  by  means  of  the  heat,,  and  the  mois- 
ture contained  in  them  or  ascending  with  the  erupted  rock. 

Hisingerite. 

Massive;  reniform.  Color  black  to  brownish  black.  Streak 
yellowish  brown.  Lustre  greasy,  inclining  to  vitreous.  H.  = 
3.  G.  =  3-045. 

Composition.  A  hydrous  iron  silicate,  (H2fFe)00]2Si3 
-|-4aq  =  Silica  35 -9,  ironsesquioxide42'6,  water  21 '5  =  100. 
In  some  analyses  part  of  the  iron  is  in  the  protoxide  state. 
B.B.  fuses  with  difficulty  to  a  magnetic  slag. 

Obs.  From  Sweden;  Norway;  Finland.  Scotiolite  and 
Degeroite  are  referred  here.  Afelunnlite,  from  Milk-Row 
quarry,  near  Charlestown,  Mass.,  is  related  in  composition,, 
if  the  material  analyzed  was  a  pure  species. 

Gillingite,  from  Sweden  (including  Thraulitefrom  Bavaria),  Lillite. 
Other  hydrous  silicates  of  iron. 

Ekmannite.  Foliated,  chlorite-like;  a  hydrous  iron  silicate,  but  the 
iron  mostly  in  the  protoxide  state.  Sweden  in  the  rifts  of  magnetite, 

Epichlorite.  Between  chlorite  and  schiller  spar;  a  hydrous  silicate 
of  aluminium,  iron,  and  magnesium.  Altered  brouzite?  In  serpen- 
tine at  Harzburg. 

Neotocite  (Stratopeite)  and  Witlingite  are  results  of  the  alteration  of 
rhodonite,  and  contain  manganese.  Stubelite  also  contains  manganese 
oxide. 

Strigomte  from  Striegau,  Jollyte  from  Bodenmais,  Huttite  from 
Ireland,  are  hydrous  silicates  of  aluminium  and  iron,  with  little  mag- 
nesium. 

Pyrosclerite. 

Orthorhombic  or  monoclinic.  Mica-like  in  cleavage;  folia 
flexible,  not  elastic.  Color  apple-green  to  emerald-green. 
Lustre  pearly.  H.  =  3.  G.  =  2  74. 

Composition.  (|Mg8iAl)a019Sia  +  3  aq  =  Silica  38 -9, 
alumina  14'8,  magnesia  34*6,  water  11-7  —  100.  B.B.  fuses 
to  a  grayish  glass;  gelatinizes  with  hydrochloric  acid. 

Obs.   Occurs  in  serpentine,  on  Elba. 

Chonicrite  (Metaxoite).  Related  to  the  above  in  composition,  but 
affords  12  to  18  per  cent,  of  lime. 

Vermiculite. 

Mica-like  in  cleavage.  In  aggregated  scales.  Also  in 
large  micaceous  crystals  or  plates.  Laminae  flexible,  not 


CHLORITE   GROUP.  339 

elastic.  Color  gray,  brown,  yellowish  brown.  Lustre 
pearly. 

Composition.  Mg3  (Fe,  Al)  0]2Si3.  Exfoliates  when 
heated,  and  when  scaly- granular  the  scales  open  out  into 
worm-like  forms;  and  thence  the  name,  from  the  Latin 
vermiculor,  to  breed  worms;  B.B.  fuses  finally  to  a  gray 
mass.  From  Milbury,  Mass. 

Jefferisite  is  a  similar  mineral  in  composition  and  exfoliation,  occur- 
ring in  broad  folia;  composition  |Mg3|(Fe,  Al)O12Si3.  In  serpen- 
tine in  Westchester,  Pa.  Citlsageeite  from  Culsagee,  North  Carolina; 
Hallite  from  Lerni,  Delaware  Co.,  Pa  ;  Protovermiculiie  from  Magnet 
Cove,  Ark. ;  Philadelphite,  from  Philadelphia,  Pa.,  are  other  micaceous 
hydrous  unisilicates,  similar  to  vermiculite  and  Jefferisite  in  exfolia- 
tion. Kerrite  and  Maconite  are  related  to  the  above;  they  are  from 
Franklin,  Macon  Co.,  North  Carolina.  The  quality  of  exfoliating  is 
due  to  the  water  present,  and  is  produced  in  some  mica  by  alteration. 
It  is  a  question  how  far  these  vermiculite-likc  species  are  alteration 
products. 

Penninite.— Chlorite  in  part.     Pennine. 

.  Rhombohedral.  Cleavage  basal  and  highly  perfect,  mica- 
like.  Also  massive,  consisting  of  an  aggregation  of  scales, 
and  cryptocrystalline.  Color  green  of  various  shades;  also 
yellowish  to  silver-white,  and  rose-red  to  violet.  Lustre 
pearly  on  cleavage  surface.  Transparent  to  translucent. 
Laminae  flexible,  not  elastic.  H.  =  2-2*5,  3  on  edges. 
G.  =2-6-2-75. 

Composition.  A  specimen  from  Zermatt,  in  the  Pennine 
Alps,  afforded  Silica  33'64,  alumina  10*64,  iron  sesquioxide 
8-83,  magnesia  34-95,  water  12 -40  =  100-46.  The  rose-red, 
from  Texas,  Pa.,  gave  Silica  33-20,  alumina  11-11,  chro- 
mium oxide  6*85,  iron  sesquioxide  1*43,  magnesia  35-54, 
water  12'95,  lithia  and  soda  0*28,  potash  010=101-46. 
Other  Texas  specimens  afforded  0-90  to  4'78  per  cent,  of 
chromium  oxide.  B.  B.  exfoliates  somewhat  and  fuses  with 
difficulty.  Partially  decomposed  by  hydrochloric  acid,  and 
wholly  so  by  sulphuric  acid. 

From  Zermatt,  Ala  in  Piedmont,  the  Tyrol,  etc.  Edm- 
mererite,  Rliodochrome,  and  KhodopJiyllite  include  the  red- 
dish variety  from  near  Miask,  Russia;  Texas,  Pa.;  etc. 
Pseudomorphs  after  hornblende,  named  Laganite,  have  the 
composition  of  this  species;  and  so  has  the  massive  mineral 
called  PseudopMte  and  Allophite. 


340  DESCRIPTIONS   OF  MINERALS. 

Delessite.  A  fibrous  chlorite  like  mineral  near  the  above  in  compo- 
sition. From  amygdaloid  at  Oberstein. 

Euraliie.  An  amorphous  chlorite,  near  Penninite.  From  Eura, 
Finland;  in  amygdaloid. 

Diabantite  (Diabantochronyri).  A  chlorite  from  amygdaloid.  A 
Farmington  (Conn.)  specimen  afforded  Hawes,  Silica  33'68,  alumina 
10*84,  iron  sesquioxide  2  '86,  iron  protoxide  24 '33,  MnO  and  CaO 
1-11,  magnesia  16'52,  soda  Q- 33,  water  10  02  =  99*69.  Steatargillite 
contains  much  iron. 

Chlorophwite.    A  doubtful  chlorite.     Amygdaloid,  in  Scotland. 

Ripidolite.— Chlorite,  in  part. 

Monoclinic.  Similar  in  cleavage  and  mica-like  character 
to  penninite,  and  also  in  its  colors,  lustre,  hardness,  and 
specific  gravity. 

Composition.  A  specimen  from  Chester  Co.,  Pennsylvania, 
afforded  Silica  31 '34,  alumina  17*47,  chromium  sesquioxide 
1*69,  iron  sesquioxide  3*85>  magnesia  33*44,  water  12*60  = 
100*39.  B.B.  and  with  acids  nearly  like  penninite.  A  va- 
riety from  Willimantic,  Ct.,  exfoliates  like  vermiculite  and 
jefferisite. 

Kotscliubeite  is  a  red  variety  from  the  Urals.  ClinocJilore 
and  Grastite  are  here  included.  Occurs  at  Achmatovsk 
and  elsewhere  in  the  Urals;  at  Ala,  Piedmont;  at  Zermatt; 
Westchester,  Union ville  and  Texas,  Pa. ;  Brewster's,  N.  Y. 

Prochlorite. — Chlorite  in  part. 

Hexagonal.  Similar  in  cleavage  and  mica-like  characters 
to  the  preceding.  Color  green  to  blackish  green;  some- 
times red  across  the  axis  by  transmitted  light.  G.  —  2  '75-3. 
Laminse  not  elastic. 

Composition.  A  specimen  from  St.  Gothard  afforded  Sili- 
ca 25 -36,  alumina  18-56,  iron  protoxide  28 -79,  magnesia 
17-09,  water  8-96  =  98  "70;  and  a  North  Carolina  specimen, 
Silica  24-90,  alumina  21*77,  iron  sesquioxide  4-60,  iron 
protoxide  24-21,  manganese  protoxide  1*15,  magnesia  12 '78, 
water  10'59  ==  100.  B.B.  same  as  for  preceding. 

Lophoite,  Ogcoite,  Helminthe  belong  here.  Occurs  at  St. 
Gothard;  Greiner  in  the  Tyrol;  Traversella  in  Piedmont, 
and  many  other  places  in  Europe.  Also  at  Steele's  Mine, 
tf.  C. 

Leuchteribergite.  A  prochlorite  with  the  base  almost  solely  magne- 
sium. Rubislite  is  a  doubtful  chlorite. 


CHLORITE   GROUP. 


341 


Aphrosiderite.  Near  prochlorite  in  composition.  Weilburg,  Ger- 
many. 

Venerite.  A  pale  green  earthy  chlorite-like  material  containing 
copper.  Berks  Co. ,  Pa. 

CorundopMlite.  Near  prochlorite.  With  corundum  at  Asheville, 
N.  C. ;  Chester,  Mass.  Amesite. 

GrocJiauite.     From  Grochau  in  Silesia. 

Cronstedtite.  Hexagonal,  with  perfect  basal  cleavage;  black;  G.  = 
3 '85;  consists  mainly  of  silica,  iron  oxides,  and  water,  with  a  little 
manganese  oxide.  Bohemia;  Cornwall. 

Ihuringite.  Another  hydrous  iron  silicate;  G.  =  3*15-3'20;  dark 
green  to  yellow-green.  Tlmringia;  Hot  Springs,  Arkansas;  near 
Harper's  Ferry,  on  the  Potomac;  Union ville,  Pa.  (Patter sonite). 

Margarite. — Emerylite.     Diphanite.     Clingmanite.     Corundellite. 

Orthorhombic.  Foliated,  mica-like.  Laminae  rather 
brittle.  Color  white,  grayish,  reddish.  Lustre  of  cleav- 
age surface  strong  pearly  and  brilliant,  of  sides  of  crystals 
vitreous.  H.  —  3'5-4-5.  G.  =  2'99. 

Composition.  H2RAl2012Si2  =  Silica  30-1,  alumina  51 '2, 
lime  11-6,  soda  2-6,  water  4*5  =  100.  B.B.  whitens  and 
fuses  on  the  edges. 

Obs.  Often  associated  with  corundum  and  diaspore.  Oc- 
curs in  Asia  Minor;  at  Sterzing  in  the  Tyrol;  in  the  Urals; 
in  Village  Green  and  Union  ville,  Pa. ;  Buncombe  County, 
N.  C. ;  Chester,  Mass.  Named  from  the  Greek  margarites, 
a  pearl. 

Willcoxite.    Near  margarite. 

Dudley  ite.    An  alteration  product  of  margarite. 

Chloritoid.— Masonite.    Phyllite.     Ottrelite. 

Monoclinic.  Cleavage  basal,  perfect.  Also  coarse  foli- 
ated massive;  and  in  thin  disseminated  scales  (pliyllite  or 
ottrelite).  Brittle. 

Color  dark  gray,  greenish,  to  black.  Lustre  of  cleavage 
surface  somewhat  pearly.  H.  =  5 '5-6.  G.  =  3 '5-3*6. 

Composition.  FeA106Si  -f-  1  aq  —  Silica  24'0,  alumina 
40 '5,  iron  protoxide  28 '4,  water  7*1  —  100.  B.B.  becomes 
darker  and  magnetic,  but  fuses  with  difficulty.  Decomposed 
completely  by  Sulphuric  acid. 

Obs.  Found  at  Kossoibrod,  Urals,  with  cyanite;  in  Asia 
Minor,  with  emery;  at  St.  Marcel  (Sismondine);  Ottrez, 
France  (Ottrelite)}  Chester,  Mass.;  in  Rhode  Island  (Ma- 


342  DESCRIPTIONS   OF   MINERALS. 

sonite);  at  Brome  and  Leeds,  Canada;  in  scales  (Phyllite) 
characterizing  the  "  spangled  mica  slate"  of  Newport,  R.  I., 
and  Sterling,  Goshen,  etc.,  Mass. 

SeyJ)ertite(Clintonite).  Monocliuic.  Thin  foliated;  somewhat  mica- 
like;  basal  cleavage  perfect;  laminae  brittle;  color  reddish  or  yellowish 
brown  to  copper- red;  lustre  pearly  submetallic.  H.  =  4'5.  G.  =3. 
Analysis  by  Brush  obtained  Silica  20*24,  alumina  39'13,  iron  sesqui- 
oxide  3'27,  magnesia  20'84,  lime  13'69,  water  T04,  potash  and  soda 
1'43,  zirconia  0'75  =  100'39,  giving  the  quantivalent  ratio  for  protox- 
ides, sesquioxides,  silica,  and  water  6  :  9  :  5  :  4-.  Amity,  N.  Y.;  Sla- 
toust,  Urals  (Xanthophyllite,  Waluewte);  Fassa  Valley  (Brandisiie  and 
Disterrite). 

3.  HYDROCARBON   COMPOUNDS. 

The  following  are  the  subdivisions  here  used: 

I.  SIMPLE  HYDROCARBONS:  Marsh-gas,  Mineral  oils,  and 
Mineral  wax. 

II.  OXYGENATED  HYDROCARBONS:  mostly  resins. 

III.  ASPHALTUM  AND  MINERAL  COALS. 

I.  SIMPLE  HYDROCARBONS. 

Marsh-Gas. — Light  Carburetted  Hydrogen.      Rock  Gas.      Natural 

Gas. 

Colorless  and  inodorous  when  pure,  burning  with  a  yel- 
low flame,  and  consisting  of  Carbon  75,  hydrogen  25  —  100 
=  CH4. 

Natural  gas  varies  in  composition  according  to  its  source, 
the  marsh-gas  being  mixed  with  more  or  less  of  nitrogen, 
carbonic  acid  (COJ,  and  some  other  ingredients.  That 
which  occurs  bubbling  up  in  marshes,  as  a  result  of  the  de- 
composition of  organic  matters  and  accompanying  deoxi- 
dation  of  the  atmosphere,  often  contains  much  nitrogen; 
Websky  finding  the  composition  in  one  case:  Marsh-gas 
43  36,  nitrogen  53 '67,  C02  2-97  =  100.  The  C02  is  in  small 
amount,  although  an  abundant  product  of  decomposition, 
because  it  enters  into  combinations  with  earthy  bases  pres- 
ent, and  is  to  some  extent  soluble  in  water. 

The  natural  gas  from  deeper  sources,  arising  occasionally 
through  springs,  and  obtained  by  borings,  such  as  is  now 
used  extensively  for  lighting  and  heating,  is  chiefly  pure 
marsh- gas,  with  often  2  or  3  p.  c.  of  nitrogen,  as  much 


SIMPLE   HYDROCARBONS.  343 

sometimes  of  carbonic  acid,  a  little  free  hydrogen,  and  occa- 
sionally very  sparingly  other  gaseous  products  of  the  marsh 
gas  series.  The  gas  of  a  well  of  Butler  Co.,  Pa.,  afforded 
marsh-gas  80*11,  hydrogen  13*50,,  carbonic  acid  0  66,  ethane 
5-72  —  99-99;  and  that  of  the  Karg  well,  Findlay,  Ohio, 
marsh-gas  92*61,  hydrogen  2 -18,  olefiant  gas  0'30,  nitrogen 
3  61,  oxygen  034,  C02  0-50,  CO  0*26,  sulphuretted  hydro- 
gen 0*20;  but  the  nitrogen  is  sometimes  in  large  propor- 
tions, up  to  25  or  30  per  cent.  Moreover,  the  same  gas- 
well  gives  a  varying  gas,  one  in  western  Pennsylvania  afford- 
ing marsh-gas  57 '85  per  cent.,  hydrogen  9  64,  nitrogen 
23-41  on  the  18th  of  October,  1884;  the  corresponding 
numbers  7516,  14'45,  2 -89  on  the  25th;  and  7218,  20 "02, 
0-00,  on  the  28th, 

The  districts  affording  natural  gas  are  usually  those  af- 
fording also  more  or  less  mineral  oil,  the  gas  and  oil  being 
related  carbohydrogen  compounds,  and  the  latter  yield- 
ing the  former.  The  strata  below  are  but  slightly  dis- 
turbed, that  is,  have  very  gentle  pitch  if  any,  and  are  un- 
crystalline.  Deep  below  the  surface  there  are  blackish 
carbonaceous  shales,  slates  or  limestones,  or  other  de- 
posits of  the  kinds  that  yield  mineral  oil  and  gas  when 
heated.  The  gas,  like  the  mineral  oil,  is  supposed  to 
be  usually  confined  in  very  porous  coarse  sandstones,  and 
not  in  open  cavities;  these  porous  strata  being  situated 
above  the  gas-yielding  stratum.  The  gas  may  have  been 
made  through  the  action  of  low  heat  on  the  blackish  car- 
bonaceous rocks  (slight  disturbances  having  occasioned  the 
heat  required). 

Beds  of  buried  vegetation  occur  in  the  drift  of  Ohio  and 
the  States  west,  and  have  been  the  source  of  some  marsh- 
gas,  "  sufficient  for  domestic  use."  But  the  large  discharges 
of  gas  in  the  United  States  are  from  older  deposits  from  the 
Tertiary  to  the  Lower  Silurian,  and  come  from  borings  to 
depths  often  of  1000  to  2000  feet  or  more.  The  wells  of 
Northwestern  Ohio  (about  Findlay)  go  down  to  the  Trenton 
limestone;  but  most  of  those  of  Western  Pennsylvania  and 
the  regions  adjoining  stop  in  the  Subcarboniferous  or  De- 
vonian. Black  shales  are  widely  distributed  over  the  globe, 
and  the  supply  may  be  long  continued,  although  becoming 
locally  exhausted  in  a  short  period. 

Natural  gas  was  first  used  for  lighting  in  Fredonia,  Erie 
Co.,  N.  Y.,  where  it  is  given  out  from  springs.  In  1872 


344  DESCRIPTIONS   OF   MINERALS. 

and  1873  the  waste  gas  of  the  petroleum- wells  of  Butler 
and  Crawford  cos.,  Pa.,  began  to  be  used  for  heating 
boilers  and  lighting.  In  1882  wells  were  sunk  in  Western 
Pennsylvania  to  obtain  gas,  and  since  then  natural  gas  has 
become  in  some  localities  in  different  States  almost  the  sole 
fuel  and  lighting  material  for  large  cities  and  villages,  with 
all  their  factories.  Even  Eastern  New  York,  at  Knowers- 
ville,  has  a  gas-well;  and  borings  are  beginning  to  be  pro- 
ductive in  the  Western  States  and  Territories.  The  gas  is 
lit  up  and  put  out  in  an  instant,  gives  a  steady  heat,  needs 
no  attention,  makes  no  ashes,  requires  no  storage  of  fuel, 
burns  without  odor,  and  yields  no  sulphur  to  injure  fur- 
naces and  products  of  manufacture,  etc. 

In  the  Murraysville  district — one  of  those  supplying 
Pittsburg — the  best  wells  afford  10,000,000  to  33,000,000 
of  cubic  feet  of  gas  per  day.  The  pressure  at  the  source  is 
commonly  200  to  300  pounds  to  the  square  inch,  but  in 
some  cases  500  to  700  pounds.  In  the  shallow  wells  of 
other  regions  (and  some  deep  wells)  the  pressure  is  often 
but  50  pounds  or  less. 

With  gas  of  average  composition,  1000  cubic  feet  have, 
theoretically,  the  heating  power  of  about  54*4  pounds  of  bi- 
tuminous coal  and  58 -4  of  anthracite  (S.  A.  Ford),  so  that 
41,000  ft.  of  gas  are  equivalent  to  2240  pounds,  or  a  ton,  of 
coal.  (( It  is  safe  to  adopt  a  practical  equivalence  of  30,000 
cubic  feet  of  gas  to  1  ton  of  coal"  (J.  P.  Lesley). 

The  first  use  of  natural  gas  for  lighting  and  heating  was 
in  China.  In  the  province  of  Sz'chuen  are  artesian  wells 
1500  to  3000  feet  deep,  yielding  brines,  oil,  and  abundant  gas. 
The  gas  is  conveyed  in  bamboos  and  used  for  evaporating 
the  brines  and  lighting.  In  the  petroleum  region  of  Baku, 
on  the  Caspian,  are  "eternal  fires"  of  similar  origin.  All 
regions  of  mineral  oil  probably  have  stored  gas  below. 

Petroleum. 

Mineral  oils,  varying  in  density  from  0'60  to  0*85.  Solu- 
ble in  benzine  or  camphene.  They  consist  chiefly  of  liquids 
of  the  Naphtha  and  Ethylene  series.  The  composition  of 
the  Naphtha  or  Marsh-g'as  series  is  expressed  by  the  general 
formula,  CnH2n  -f  2,  of  which  Marsh-gas  is  the  first  or 
lowest  term;  and  that  of  the  Ethylene  series  by  the  for- 
mula, CnH2n  =  Carbon  85 '71,  hydrogen  14-29  =  100.  The 


SIMPLE   HYDROCARBONS.  345 

oils  vary  greatly  in  density  from  the  lightest  naphtha,  too 
inflammable  for  use  in  lighting,  to  thick  viscid  fluids ;  and 
thence  they  pass  by  insensible  gradations  into  asphaltum  or 
solid  bitumen.  The  Marsh-gas  series  contains  also  gases, 
of  the  composition  02H6  and  C3H8  and  these,  in  addition 
to  Marsh-gas,  often  exist  in  connection  with  petroleum. 

Petroleum  occurs  in  rocks  of  all  ages,  from  the  Lower 
Silurian  to  fhe  most  recent;  in  limestones,  porous  or  com- 
pact sandstones,  and  shales;  but  it  is  mostly  obtained  from 
cavities  existing  among  the  earth's  strata  or  more  probably 
from  the  porous  strata  themselves.  Black,  shales  and  much 
bituminous  coal  afford  it  abundantly  when  they  are  heated; 
but  the  oil  obtained  is  not  present  in  these  rocks,  for  when 
the  rocks  are  treated  with  benzine,  the  benzine  takes  up 
little  or  none;  instead,  the  rocks  contain  an  insoluble  hydro- 
carbon, which  yields  the  oil  when  heat  is  applied. 

In  the  United  States  the  oil,  or  the  hydrocarbon  which 
yields  it,  has  been  observed  in  beds  of  the  Lower  and  Upper 
Silurian,  Devonian,  Carboniferous,  Triassic,  Cretaceous,  and 
Tertiary  eras.  Surface  oil-springs  also  occur  in  many  places. 
Foreign  regions  noted  for  mineral  oil  are  Rangoon  in  Bur- 
mah,  where  there  are  about  100  wells;  at  Baku  on  the  Cas- 
pian, whose  springs  promise  to  supply  Russia  and  Europe 
with  petroleum.  Pliny  mentions  the  oil  spring  of  Agrigen- 
tum,  Sicily,  and  says  that  the  liquid  was  collected  and  used 
for  burning  in  lamps,  as  a  substitute  for  oil.  Moreover  he 
distinguishes  the  oil  from  the  lighter  and  more  combustible 
naphtha,  a  locality  of  which  about  the  sources  of  the  Indus, 
"in  Parthia,"  he  mentions. 

Petroleum  is  obtained  chiefly  at  the  present  time  from 
porous  oil  "sands"  (coarse  sandstones),  or  cavities  between 
or  within  the  rock  strata,  reached  by  boring.  Being  under 
pressure  from  the  gas  associated  with  it,  and  also,  in  many 
cases,  that  of  water,  it  rises  to  the  surface  in  the  boring,  and 
sometimes  makes  a  "spouting"  well.  As  early  as  1833, 
Hildreth  mentioned  the  discharge  of  oil  with  the  waters 
of  the  salt  wells  of  the  Little  Kanawha  Valley,  and  speaks 
also  of  a  well  near  Marietta,  Ohio,  which  threw  out  at  one 
time,  he  says,  50  to  60  gallons  of  oil  at  "each  eruption." 
The  great  oil -districts  of  Pennsylvania  are  the  Venango  in 
the  western  part,  and  the  Bradford  in  the  northern  (McKean 
Co.),  which  extends  5  m.  beyond  the  New  York  boundary. 
Oil  is  also  obtained  in  Ohio,  25  m.  N.  of  Zanesville,  and 


346  DESCRIPTIONS   OF   MINERALS. 

in  Kentucky  and  West  Virginia,  but  not  abundantly. 
There  are  also  productive  wells  in  California  in  the  San 
Fernando  district,  Los  Angeles  Co.,  and  in  Ventura  Co. 
There  are  also  wells  in  Colorado  and  Wyoming. 

The  mineral  oil  of  the  rocks  has  been  formed  through 
the  decomposition  of  animal  and  vegetable  substances. 
From  the  nature  of  the  shales  which  most  abound  in  the 
species  of  hydrocarbons  that  yield  oil,  it  is  'evident  that 
the  rock  material  of  the  shales  was  in  the  state  of  a  fine 
mud;  that  through  this  mud  much  vegetable  or  animal 
matter  was  distributed,  almost  in  the  condition  of  an  emul- 
sion; that  the  stratum  of  mud  becoming  afterward  over- 
laid by  other  strata,  the  decomposition  of  vegetable  or 
animal  matter  went  forward  without  the  presence  of  atmo- 
spheric air,  or  with  only  very  little  of  it.  Under  such  cir- 
cumstances either  vegetable  material  or  animal  oils  might 
be  converted,  as  chemists  have  shown,  into  mineral  oil. 
Dry  wood  consists  approximately  (excluding  the  ash  and 
nitrogen)  of  6  atoms  of  carbon  to  9  of  hydrogen,  and  4  of 
oxygen.  If  now  all  the  oxygen  of  the  wood  combines  with 
a  part  of  the  carbon  to  form  carbonic  acid,  and  this  2C02, 
thus  made,  is  removed,  there  will  be  left  C4H^;  twice  this, 
CfiH18,  is  the  formula  of  a  compound  of  the  Marsh-gas  or 
Naphtha  series.  Again  animal  oils,  by  decomposition  under 
similar  circumstances,  produce  like  results.  Eemoving  from 
oleic  acid  its  oxygen,  02,  and  1  of  carbon — the  two  together 
equivalent  to  1  of  carbonic  acid — there  is  left  C17H34,  which 
is  an  oil  of  the  Ethylene  series.  So  margaric  acid  would 
leave,  in  the  same  way,  C16H34,  or  a  combination  of  oils  of 
the  Marsh-gas  or  Naphtha  series.  Warren  and  Storer  have 
obtained  from  the  destructive  distillation  of  a  fish-oil,  after 
its  saponification  by  lime,  several  compounds  of  the  Marsh- 
gas  series,  besides  others  of  the  Ethylene  and  Benzole  series. 
The  decompositions  in  nature  may  not  have  been  as  simple 
as  those  in  the  above  illustrations,  yet  the  facts  warrant  the 
inference  that  the  oils  may  have  been  derived  either  from 
vegetable  or  animal  matters.  Fossil  fishes  are  often  found 
abundantly  in  black  oil-yielding  shales,  and  Dr.  Newberry 
has  suggested  that  fish-oil  may  be  the  most  abundant  source 
of  the  oil  and  the  oil-yielding  hydrocarbons. 

The  oil  which  is  collected  in  porous  sandstones  or  cavities 
among  the  strata,  as  in  Western  Pennsylvania,  is  believed  by 
most  writers  on  the  subject  to  have  come  from  underlying 


SIMPLE   HYDROCARBONS.  347 

rocks,  such  as  the  black  oil-yielding  shales.  The  heat  pro- 
duced in  the  rocks  by  the  friction  attending  movements  and 
uplifts  is  supposed  to  have  been  sufficient  to  have  made  the 
oil  from  the  hydrocarbon  of  the  carbonaceous  shale  or  other 
rock,  and  to  have  caused  it  to  ascend  among  the  strata  to 
the  cavities  or  porous  " sands"  where  it  was  condensed, 
and  now  is  found  by  boring. 

The  oils,  exposed  to  the  air  and  wind,  undergo  change  in 
three  ways.  First :  the  lighter  naphthas  evaporate,  leaving 
the  denser  oils  behind,  and,  ultimately,  the  viscid  bitumens; 
or  else  paraffin,  according  as  paraffin  is  present  or  not  in 
the  native  oil.  At  the  naphtha  island  of  Tschelekan,  in 
Persia,  there  are  large  quantities  of  Neft-yil,  as  it  is  called, 
which  is  nearly  pure  paraffin.  The  hot  climate  of  the  Cas- 
pian is  favorable  for  such  a  result.  Secondly :  there  may 
be  a  loss  of  hydrogen  from  its  combination  with  the  oxygen 
of  the  atmosphere  to  form  water,  which  escapes.  Thus  the 
oils  of  the  Naphtha  series  may  change  into  those  of  the 
Ethylene  or  Benzole  series.  Thirdly:  there  may  be  an 
oxidation  of  the  hydrocarbon  of  the  oils,  producing  asphal- 
tum  or  more  coal-like  substances,  like  albertite. 

The  word  naphtha  is  from  the  Persian,  nafdta,  to  exude; 
and  petroleum  from  the  Greek,  petros,  rock,  and  the  Latin, 
oleum,  oil. 

Hatchettite.— Mountain  Tallow.     Hatchettine. 

Like  soft  wax  in  appearance  and  hardness,  of  a  yellowish 
white  to  greenish  yellow  color. 
Composition.  Related  to  paraffin. 
From  the  coal-measures  of  Glamorganshire  in  Wales. 

Ozocerite.  Like  wax  or  spermaceti  in  consistence :  soluble  in  ether. 
The  original  was  from  Moldavia;  along  with  another  wax-like  sub- 
stance, called  Urpethite,  it  constitutes  the  "mineral  wax  of  Urpeth 
Colliery."  Zietrisikite  is  like  beeswax,  and  is  insoluble  in  ether; 
from  Moldavia.  Prosepnyte,  of  the  mercury  mine,  Wake  Co.,  Cal., 
is  near  ozocerite.  A  large  deposit  of  ozocerite,  or  a  related  material, 
is  worked  in  Southern  Utah. 

Elaterite. — Mineral  Caoutchouc.     Elastic  Bitumen. 

In  soft  flexible  masses,  somewhat  resembling  caoutchouc 
or  India-rubber.  Color  brownish  black ;  sometimes  orange- 
red  by  transmitted  light.  G.  =  0*9-1  '25.  Composition: 


348  DESCRIPTIONS   OF   MINERALS. 

Carbon  85-5,  hydrogen  13 '3  —  98*8.     Burns  readily  with  a 
yellow  flame  and  bituminous  odor. 

Obs.  From  a  lead-mine  in  Derbyshire,  England,  and  a 
coal-mine  at  Montrelais.  Has  been  found  at  WoocLbury, 
Ct.,  in  a  bituminous  limestone. 

Fichielite  and  Hartite  are  crystallized  hydrocarbons,  of  the  Cam- 
phene  series  ;  the  former  is  mentioned  from  a  log  of  Pinus  Australis 
in  Alabama.  BrancMte,  Dinite,  and  Ixolyte  are  related  to  Hartite. 
Konlite,  Naphthalin,  and  Idrialite  are  native  species  of  the  Benzole 
series.  Aragotite,  from  California,  is  near  Idrialite. 

II.  OXYGENATED  HYDROCARBONS. 
Amber. 

In  irregular  masses.  Color  yellow,  sometimes  brownish 
or  whitish;  lustre  resinous.  Transparent  to  translucent. 
H.  =  2-2-5.  G.  =118.  Electric  by  friction. 

Amber  is  not  a  simple  resin,  but  consists  mainly  (85  to  90 
per  cent.)  of  a  resin  which  resists  all  solvents,  called  Suc- 
cinite, and  two  other  resins  soluble  in  alcohol  and  ether, 
besides  an  oil,  and  2^  to  6  per  cent,  of  Succinic  acid. 

Obs.  Occurs  in  the  loose  deposits  of  sand,  etc.,  along 
coasts,  especially  those  of  Tertiary  strata,  in  masses  from  a 
very  small  size  to  that  of  a  man's  head.  In  the  Royal 
Museum  at  Berlin  there  is  a  mass  weighing  18  pounds. 
Most  abundant  on  the  Baltic  coast,  especially  between 
Konigsberg  and  Memel;  also  on  the  Adriatic;  in  Poland; 
on  the  Sicilian  coast  near  Catania;  in  France  near  Paris,  in 
clay;  in  China.  It  has  been  found  in  the  U.  States,  at  Gay 
Head,  Martha's  Vineyard,  and  on  Nantucket;  Camden,  and 
near  Harrison ville  (one  mass  20x6x1  in.),  N.  J.;  and  at 
Cape  Sable,  near  the  Magothy  River,  Md. ;  Pitt  Co.,  and 
other  eastern  counties,  N.  C. 

It  is  supposed,  with  good  reason,  to  be  a  vegetable  resin 
altered  somewhat  chemically  since  burial,  partly  owing  to 
acids  of  sulphur  proceeding  from  decomposing  pyrites  or 
some  other  source.  It  often  contains  insects,  and  speci- 
mens of  this  kind  are  so  highly  prized  as  frequently  to  be 
imitated  for  the  shops.  Some  of  the  insects  appear  evi- 
dently to  have  struggled  after  being  entangled  in  the  then 
viscous  resin,  and  occasionally  a  leg  or  a  wing  is  found  some 
distance  from  the  body,  which  had  been  detached  in  the 
effort  to  escape. 


ASPHALTUM  AND   MINEKAL   COALS.  349 

Amber  is  the  elefctron  of  the  Greeks;  from  its  becoming 
electric  so  readily  when  rubbed,  it  gave  the  name  electricity 
to  science.  It  was  also  called  succinum,  from  the  Greek 
SHccum,  juice,  because  of  its  supposed  vegetable  origin. 

It  admits  of  a  good  polish,  and  is  used  for  ornamental 
purposes,  though  not  very  much  esteemed,  as  it  is  wanting 
in  hardness  and  brilliancy  of  lustre,  and  moreover  is  easily 
imitated.  It  is  much  valued  in  Turkey  for  mouth-pieces 
to  pipes. 

Copalite,  or  Mineral  Copal,  Gedaniie,  Walchowite,  Neudorfite,  Schrau- 
fite,  Ami/rite  (the  New  Zealand  resin),  Euosmite,  Scleretinite,  Middle- 
tonile,  Ajkite,  Duxite,  Krantzite,  Siegburgite,  arc  some  of  the  names  of 
other  fossil  resins  ;  Oeocerite,  and  Oeomyridte,  of  wax-like  oxygenated 
species;  Ouyaquillite,  Bathmllite,  lonile  (from  lone  valley,  Cal.),  of 
species  not  resinous  in  lustre  ;  Tasmanite  and  Dysodile,  of  kinds  con- 
taining several  per  cent,  of  sulphur.  Celestialite  is  a  probable  sul- 
pho-hydrocarbon  from  a  meteorite.  Torbanite,  or  Boghead  coal,  is 
related  in  composition  to  amber.  Wollongongite,  from  Hartley  (not 
Wollongong),  Australia,  looks  like  cannel  coal,  but  is  near  torbanite. 

Dopplerite.  Elastic  or  partly  jelly-like,  and  from  a  peat-bed.  A 
similar  material,  from  a  peat-bed  in  Scranton,  Pa.,  has  been  named 
Phytocollite. 

Hofmannite.  White  efflorescence  on  lignite  ;  in  tabular  crystals  ; 
fuses  easily  to  an  oily  fluid,  and  burns  with  a  bright  flame.  Formula 
CaoHaeO.  From  near  Siena,  Italy. 


III.  ASPHALTUM  AND  MINERAL  COALS. 
Asphaltum. 

Amorphous  and  pitch-like.  Burning  with  a  bright  flame 
and  melting  at  90°  to  100°  F.  Soluble  mostly  or  wholly  in 
camphene.  A  mixture  of  hydrocarbons,  part  of  which  are 
oxygenated. 

Obs.  Asphaltum  is  met  with  abundantly  on  the  shores  of 
the  Dead  Sea,  and  in  the  neighborhood  of  the  Caspian;  A 
remarkable  locality  occurs  on  the  island  of  Trinidad,  where 
there  is  a  lake  of  it  about  a  mile  and  half  in  circumference. 
The  bitumen  is  solid  and  cold  near  the  shores;  but  grad- 
ually increases  in  "temperature  and  softness  toward  the 
centre,  where  it  is  boiling.  The  ascent  to  the  lake  from 
the  sea,  a  distance  of  three  quarters  of  a  mile,  is  covered 
with  the  hardened  pitch,  on  which  trees  and  vegetation 
flourish,  and  here  and  there,  about  Point  La  Braye,  the 
masses  of  pitch  look  like  black  rocks  among  the  foliage. 


350  DESCRIPTIONS   OF  MINERALS. 

Occurs  also  in  South  America  about  similar  lakes  in  Peru, 
where  it  is  used  for  pitching  boats;  in  California  on  the 
coast  of  Santa  Barbara.  Large  deposits  occur  in  sandstone 
in  Albania.  Uintahite,  from  Uintah  Mts.,  Utah,  is  similar. 

Albertite. 

Coal-like  in  hardness,  but  little  soluble  in  camphene,  and 
only  imperfectly  fusing  when  heated;  but  having  the  lustre 
of  asphaltum,  and  softening  a  little  in  boiling  water.  H.  = 
1-2.  G.=  1-097. 

Fills  fissures  in  the  Subcarboniferous  rocks  near  Hills- 
borough,  Nova  Scotia;  supposed  to  have  been  derived  from 
the  hydrocarbon  of  the  adjoining  rock,  and  to  have  been 
oxidized  at  the  time  it  was  formed  and  filled  the  fissure. 

GraJiamite.  A  related  material  from  West  Virginia,  20  miles  south 
of  Parkersburg  (also  from  Huastcca,  Mexico).  H.  =  2;  G.^1145; 
soluble  mostly  in  camphene,  but  melt  sonly  imperfectly;  an  anatysis 
afforded  Carbon  76'45,  hydrogen  7 '82,  oxygen  (with  traces  of  nitrogen) 
13-46,  ash  2'26  =  100. 


MINERAL  COAL. 

/ 

Massive,  uncrystalline.  Color  black  or  brown;  opaque. 
Brittle  or  imperfectly  sectile.  H.  =  0-5-2  5.  G.  —  T2- 
1*80. 

Composition.  Carbon,  with  some  oxygen  and  hydrogen, 
more  or  less  moisture,  and  traces  also  of  nitrogen,  besides 
some  earthy  material  which  constitutes  the  ash.  The  car- 
bon, or  part  of  it,  is  in  chemical  combination  with  the 
hydrogen  and  oxygen.  Often  contains  some  occluded 
marsh  gas,  whose  escape,  as  pressure  is  removed,  is  one 
source  of  the  gas  of  coal-mines. 

Coals  differ  in  the  amount  of  volatile  ingredients  given 
off  when  heated.  These  ingredients,  besides  moisture  and 
some  sulphur,  are  hydrocarbon  oils  and  gas,  derived  from 
the  same  class  of  insoluble  hydrocarbons  that  is  the  source 
of  the  oil  of  shales  and  other  rocks. 

VARIETIES. 

1.  Anthracite.  (Glance  coal,  Stone  coal).  Lustre  high, 
not  resinous,  sometimes  submetallic.  Color  gray-black. 
H.  =  2-2-5.  G.  =  1-57-1-67,  if  pure.  Fracture  often 


MINERAL   COAL.  351 

conchoidal.  Good  anthracite  contains  78  to  88  per  cent, 
of  fixed  carbon  (83  about  an  average)  2  to  3*5  of  hydrogen, 
1'5  to  3*5  of  oxygen  with  4  to  12  p.  c.  of  earthy  impurities. 
The  amount  of  volatile  matter  is  but  3  to  7  p.  c.,  and  there  is 
a  trace  of  sulphur.  Burns  with  a  feeble  blue  flame.  The 
kind  yielding  the  most  volatile  ingredients  is  called  free- 
buniing  anthracite. 

2.  Bituminous  coal.     Color  and  powder  black.     Lustre 
usually  somewhat  resinous.      H.  =  1*5-2.      G.  =  1 '2-1*4, 
if  pure;  the  Pittsburg,  1'23-1'28.     Contains  usually  75  to 
85  p.  c.  of  carbon,  4  to  6  of  hydrogen,  4  to  15  of  oxygen, 
with  mostly  2  to  9  p.  c.  of  moisture.     The  volatile  carbo- 
hydrogen  ingredients  20  to  45  p.  c.,  with  50  to  over  60  in 
some  kinds;  sulphur  in  the  best  coals  below  1  p.  c.,  but 
often  2  to  2*5.     Ash  impurities  1*4-7*5  p.  c.;  average  5  or 
6  p.  c. ;  less  than  in  anthracite,  because  anthracite  was  made 
out  of  bituminous  coal  by  the  expulsion  of  volatile  ingredi- 
ents— a  condensing  process.     Burns  with  a  bright  yellow 
flame.    Yields  little  to,  or  colors  slightly,  if  at  all,  a  potash 
solution. 

Caking  Coal  includes  that  part  of  bituminous  coal  which 
softens  when  heated  and  becomes  viscid,  so  that  adjoining 
pieces  unite  into  a  solid  mass.  It  burns  readily  with  a  lively 
yellow  flame,  but  requires  frequent  stirring  to  prevent  its 
agglutinating,  and  so  clogging  the  fire.  Non-caking  coal 
resembles  the  caking  in  appearance,  but  does  not  soften  and 
cake.  The  chemical  difference  between  caking  and  non- 
caking  coal  is  not  understood. 

3.  Cannel  Coal.    Very  compact  and  even  in  texture,  with 
little  lustre,   and  fracture  large  conchoidal.      Takes  fire 
readily,  and  burns  without  melting  with  a  yellow  flame,  and 
has  hence  been  used  for  candles — whence  the  name.    Vola- 
tile  carbohydrogen    compounds   given   out   when    heated 
amount  to  40  to  50  p.  c.,  and  even  60;  and  hence  valued 
for  the  manufacture  of  gas  as  well  as  for  fuel;  also  yields 
much  mineral  oil.     Cannel  coal  is  often  made  into  ink- 
stands and  other  similar  articles. 

4.  Brown  Coal  (often  called  Lignite).     Color  black  to 
brownish  black;  of  powder,  brown.    Contains  15  to  20  p.  c. 
of  oxygen,  and  often  8  to  10  p.  c.  of  hygrometric  moisture; 
fixed  carbon  mostly  52  to  65  p.  c.     Gives  a  brownish  or 
brownish  red  color  to  a  solution  of  potash.     Usually  non- 
caking.    The  kinds  having  more  or  less  of  the  structure  of 


352 


DESCRIPTIONS   OF   MINERALS. 


wood  are  called  lignite;  and  in  these  kinds,  the  oxygen, 
present  may  be  '25  to  over  30  p.  c.,  and  the  moisture  15  to  20 
p.  c.  Between  the  brown  coals  and  bituminous  coal  there 
is  a  gradual  passage  in  constitution  and  in  color  of  powder. 

Jet  resembles  cannel  coal,  but  is  harder,  of  a  deeper  black 
and  higher  lustre.  It  receives  a  brilliant  polish,  and  is  set 
in  jewelry.  It  is  the  Gagatcs  of  Dioscorides  and  Pliny,  a 
name  derived  from  the  river  Gagas,  in  Syria,  near  the 
mouth  of  which  it  was  found,  and  the  origin  of  the  term 
jet  now  in  use.  Occurs  in  the  Lower  Oolite  in  Yorkshire. 

Native  Colce  resembles  somewhat  artificial  coke,  but  is 
more  compact,  and  some  varieties  of  it  afford  a  consider- 
able amount  of  bitumen.  Occurs  at  the  Edgehill  mines 
near  Richmond,  Virginia,  according  to  Genth,  who  attrib- 
utes its  origin  to  the  action  of  a  t  trap  eruption  on  bitumi- 
nous coal. 

The  following  are  a  few  analyses  of  bituminous  coals,  etc., 
the  moisture  excluded: 


Car- 
bon. 

Hydr. 

Oxyg. 

Nitr. 

Sulph. 

Ash. 

Caking  Coal,  Kentucky  
Caking  Coal,  Nelson  viile,  O  
Caking  Coal,  South  Wales  
Caking  Coal,  Northumberland  
Non-caking,  Kentucky  
Non-caking,  "Black  Coal,"  Ind... 
Non-caking,  Briar  Hill.  O  
Non-caking,  S.  Staffordshire  
Non-caking,  Scotland  

74-45 
73-80 
82-56 
78-69 
77-89 
82-70 
78-94 
76-40 
76-08 

4-93 
5-79 
5-36 
6-00 
5-42 
4-77 
5-92 
4-62 
5  31 

13-08 
16-58 
8-22 
10-07 
12-57 
9-39 
11-50 
17-43 
13-33 

1-03 
1-52 
1  «5 
2  37 
1-82 
1-62 
1-58 

2  :09 

0-91 
0'41 
0  75 
1-51 
3-00 
0-45 
0-56 
0-55 
1  23 

5-00 
1-90 
1-46 
1-36 
2  00 
1-07 
1-45 
1-55 
1'96 

Cannel  Coal,  Breckenridge  
Cannel  Coal,  Wigan  

68-13 
80'07 

6  49 
5-53 

5-83 
8'10 

2-27 
2-12 

2-48 
1'50 

12-30 
2'70 

Cannel  Coal,  "  Torbanite"  
Albertite  Nova  Scotia 

64-02 
86-04 

8-90 
8'96 

5-66 
1"97 

0-55 
2'93 

0  50 

20-32 
O'lO 

Brown  Coal,  Bovey  
Brown  Coal,  Wittenberg. 

66-31 
64'07 

5-63 
5-03 

22-86 
27'55 

0-57 

2-36 

2-27 
3'85 

Brown  Coal,  Carbon,  Wy  
Brown  Coal,  Carbon,  Wy  
Peat,  light  brown  (imperfect)  
Peat  dark  brown 

73-55 
75-20 
50-86 
59'47 

4-17 
4-74 
5-80 
6  '52 

17-20 
10-37 
42-57 
31"51 

1  93 

1-37 
0  77 
2  "51 

1-18 
1-11 

1-86 
7-20 

Peat,  black  

59  70 

5'70 

as  -04 

1'56 

Peat,  black          .               

59'71 

5'27 

32'07 

2'59 

It  is  now  well  established  that  mineral  coal  is  mainly  of 
vegetable  origin,  and  that  the  accumulations  out  of  which 
the  coal-beds  were  made  were  very  similar  in  character, 
though  not  in  kinds  of  plants,  to  the  peat-beds  of  the  pres- 
ent day.  Peat  is  vegetation  which  has  undergone,  in  part, 
the  change  to  coal;  and  in  some  cases  it  has  become  brown 
coal.  The  conditions  of  change  are  somewhat  different  from 


MINERAL   COAL.  353 

those  of  the  beds  of  good  coal,  since,  in  the  case  of  the  peat, 
the  air  has  access,  while  in  that  of  the  coal  the  air  was  more 
or  less  excluded  by  overlying  strata;  and  the  more  perfect 
the  exclusion,  other  things  equal,  the  better  the  coal.  As 
the  composition  of  mineral  coal  is  closely  related  to  that  of 
mineral  oils,  the  explanation  of  the  origin  of  the  latter, 
given  on  page  346,  suffices  to  illustrate  also  the  origin  of 
the  former.  With  a  less  complete  exclusion  of  the  air, 
oxygenated  hydrocarbon  compounds,  like  coal,  would  be  a 
natural  result. 

The  "Mineral  Charcoal"  of  coal  beds  differs  little  in  composition 
from  ordinary  bituminous  coal;  there  is  less  hydrogen  and  oxygen. 
Rowney  obtained,  for  that  of  Glasgow  and  Fifeshire,  Carbon  82 '97, 
74-71;  hydrogen  3'34,  2'74;  oxygen  7'59,  7  67;  ash  6  08,  14 '86.  The 
nitrogen  is  included  with  the  oxygen;  it  was  0'75  in  the  Glasgow  char- 
coal. Exclusive  of  the  ash,  the  composition  is  Carbon  88'36,  87'78; 
hydrogen  3'56,  3'21;  oxygen  7'28,  9'01.  It  has  a  fibrous  look,  and 
occurs  covering  the  surfaces  between  layers  of  coal,  and  has  been  ob- 
served in  coal  of  all  ages.  It  is  soft,  and  soils  the  fingers  like  char- 
coal; one  variety  of  it  is  a  dry  powder. 

The  ordinary  impurities  of  coal,  making  up  its  ash,  are  silica,  a 
little  potash  and  soda,  and  sometimes  alumina,  with  often  oxide  of 
iron,  more  or  less  pyrite  or  iron  sulphide;  besides,  in  the  less  pure 
kinds,  more  or  less  clay  or  shale.  The  amount  of  ash  does  not  ordina- 
rily exceed  8  per  cent. ,  but  it  is  sometimes  30  per  cent. ;  and  rarely  it 
is  less  than  5  per  cent.  When  not  over  3  or  4  per  cent,  the  whole  may 
have  come  from  the  plants  which  contributed  the  most  of  the  material 
of  the  coal,  since  the  Lycopods  have  much  alumina  and  lime  sulphate 
in  the  ash,  and  the  Equiseta  much  silica. 

There  is  present,  in  most  coal,  traces  of  iron  sulphide  (pyrite, 
marcasite,  or  pyrrhotite),  sufficient  to  give  sulphur  fumes  to  the  gases 
from  the  burning  coal,  and  sometimes  enough  to  make  the  coal  value- 
less in  metallurgical  operations.  Some  thin  layers  are  occasionally 
full  of  concretionary  pyrite.  The  sulphur  was  derived  from  the  plants 
or  from  animal  life  in  the  waters.  Sulphur  also  occurs,  in  some  coal 
beds,  as  a  constituent  of  a  resinous  substance;  and  Wormley  has  shown 
that  part  of  the  sulphur  in  the  Ohio  coals  is  in  some  analogous  state, 
there  being  not  iron  enough  present  to  take  the  whole  into  combina- 
tion. 

The  average  amount  of  ash  in  eighty-eight  coals  from  the  southern 
half  of  Ohio,  according  to  Wormley,  is  4'718  percent.;  in  sixty-six 
coals  from  the  northern  half,  5*120;  in  all,  from  both  regions,  4'891; 
or,  omitting  ten,  having  more  than  ten  per  cent,  of  ash,  the  average  is 
4*28.  In  eleven  Ohio  cannels,  the  average  amount  of  ash  was  12-827. 
The  moisture  in  the  Ohio  coals,  according  to  the  analyses  of  Wormley, 
varies  from  I'lO  to  9'10  per  cent,  of  the  coal.  In  the  Pittsburg  coal 
(see  analysis  8,  above),  the  best  of  the  bituminous,  the  amount  of  ash 
is  3  to  4-5  p.  c.,of  moisture  l'3-l'o  p.  c.,of  sulphur  less  than  0'25  p.  c. 


354  DESCRIPTIONS   OF   MINERALS. 

The  volatile  ingredients  of  bituminous  coal  when  purified  are  the 
gas  used  in  illumination.  It  consists  of  marsh-gas  and  hydrogen  (near 
80  p.  c.  of  the  two)  with  other  heavier  hydrocarbon  vapors;  some  car- 
bon oxide,  usually  two  per  cent,  or  so  of  moisture,  with  traces  of 
carbon  dioxide  and  nitrogen. 

The  value  of  coal  as  fuel,  supposing  its  impurities  excluded,  depends 
on  its  density,  the  amount  of  moisture  present,  the  amount  of  oxygen 
present. 

If  100  pounds  of  coal  contain  20  per  cent,  of  oxygen,  this  oxygen 
is  20  pounds  of  incombustible  material;  which  serves,  it  is  true,  to 
produce  combustion  in  the  other  ingredients,  but  in  this  only  does 
work  which  atmospheric  oxygen  may  do  as  well ;  and  further,  it  pro- 
duces water  by  combination  with  hydrogen  of  the  coal  and  so  wastes 
part  of  the  fuel. 

If  the  100  pounds  contain  10  per  cent,  of  moisture,  this  is  10  pounds 
of  incombustible  material,  which  uses  the  heat  derived  from  the  com- 
bustion of  the  other  ingredients  in  order  to  take  the  form  of  vapor 
and  escape. 

If  much  impurity — ash — is  present,  so'that  a  slag  is  formed  by  the 
fusion,  the  heat  used  in  producing  and  sustaining  this  fusion  is  so 
much  lost  to  the  furnace. 

Moreover,  the  hydrocarbon  gases  that  escape,  producing  flame,  take 
up  and  dissipate  much  heat. 

On  account  of  the  conditions  stated,  anthracite  is  the  best  fuel  for 
producing  high  heat.  But  for  making  steam  in  boilers  flame  is  desir- 
able, and  this  requires  that  the  coal  should  contain  more  hydrogen 
than  exists  in  anthracite;  the  semi-anthracite  ranks  among  the  best  in 
this  respect,  since  it  burns  with  flame  and  practically  no  smoke;  hence 
it  is  sometimes  called  "  steam  coal."  Most  bituminous  coals  contain 
too  much  hydrogen,  or  yield,  on  heating,  too  much  of  volatile  hydro- 
carbons, for  the  most  economical  production  of  steam,  or  for  metal- 
lurgical purposes,  and  hence  the  process  adopted  of  subjecting  the  coal 
(the  caking  kind  only  is  so  used)  to  partial  half-smothered  combustion, 
and  obtaining  thus  what  is  called  coke.  The  coking  drives  off  also 
from  an  eighth  to  a  fourth  of  the  sulphur  present  as  pyrite  or  other- 
wise. The  coke  obtained  is  usually  about  60  to  70  p.  c.  by  weight  of 
the  coal  used,  but  is  of  greater  bulk. 

The  calorific  power  of  a  coal — dependent  on  the  number  of  pounds 
of  water  that  may  be  evaporated  in  the  complete  combustion  of  a  given 
amount  of  the  coal — may  be  calculated  from  the  amount  of  combusti- 
ble material,  in  the  form  of  hydrogen  and  carbon,  that  is  not  lost, 
during  the  burning,  from  combination  with  the  oxygen  of  the  coal. 

Since  1  part  by  weight  of  hydrogen  combines,  in  the  combustion, 
with  8  of  oxygen  to  form  water,  an  anthracite  consisting,  ash  ex- 
cluded, of  100  of  carbon  to  2*84  of  hydrogen  and  1'74  of  oxygen,  will 
have  2 -62  of  "  disposable  hydrogen,"  the"  1*74  of  oxygen  carrying  off 
1'74  -*-  8  or  0*22  p.  c.  of  the  hydrogen;  and  a  bituminous  coal,  con- 
sisting of  100  carbon  to  612  of  hydrogen  and  21 '23  of  oxygen,  will 
have  3 '47  of  "  disposable  hydrogen,"  the  21 '23  of  oxygen  carrying  off 
2*65  of  the  hydrogen.  If  then  the  coal  contained  no  impurities,  and 
the  combustion  were  complete  (union  with  oxygen,  converting  all  the 
carbon  to  carbon  dioxide  and  all  the  hydrogen  to  water),  and  there  were 


MINERAL   COAL.  355 

no  loss  of  heat  by  radiation  or  otherwise,  the  amount  of  heat  it  would 
generate,  or  its  pyrogenic  power,  would  be  directly  deduced  from 
that  of  one  pound  of  carbon  2731°  C.,  and  an  equal  weight  of  hydrogen 
2750°  C.  This  gives  only  a  theoretical  result,  since  the  loss  of  heat  in 
practice  is  large,  and  from  several  sources,  as  already  indicated.  Bat 
the  amount  of  "disposable"  hydrogen  determines  the  value  of  the 
coal  in  gas-production.  In  Wigan  Cannel  there  are  only  about  8  per 
cent,  of  oxygen,  and  hence  4'5  p.  c.  of  "  disposable"  hydrogen;  while 
in  Boghead  Cannel,  or  Torbanite,  the  "  disposable"  hydrogen  is  over 
8  per  cent. 

Mineral  coal  occurs  in  extensive  beds  or  layers,  interstratified  with 
different  rock  strata.  The  associate  rocks  are  usually  clay  shales  (or 
slaty  beds)  and  sandstones;  and  the  sandstones  are  occasionally  coarse 
grit  rocks  or  conglomerates.  There  are  sometimes  also  beds  of  lime- 
stone alternating  with  the  other  deposits. 

Coal-beds  vary  in  thickness  from  a  fraction  of  an  inch  to  50  feet. 
The  thickness  of  a  bed  may  increase  or  diminish  much  in  the  course  of 
a  few  miles,  or  the  coal  may  become  too  shaly  to  work. 

The  areas  of  the  ' '  coal-measures"  of  the  Carboniferous  era,  in  the 
United  States,  are  as  follows: 

1.  A  small  area  in  Rhode  Island,  continued  northward  into  Massa- 
chusetts. 

2.  A  large  area  in  Nova  Scotia  and  New  Brunswick,  stretching  east- 
ward and  westward  from  the  head  of  the  Bay  of  Fundy. 

These  two  areas  are  now  separated;  but  it  is  probable  that  they  were 
once  united  along  the  region,  now  submerged,  of  the  Bay  of  Fundy 
and  Massachusetts  Bay. 

3.  The  Alleghany  Region,  which  commences  at  the  north  on  the 
southern  borders  of  New  York,  and  stretches  southwestward  across 
Pennsylvania,  West  Virginia,  and  Tennessee  to  Alabama,  and  west- 
ward over  part  of  Eastern  Ohio,  Kentucky,  Tennessee,  and  a  small 
portion  of  Mississippi.     It  may  underlie  the  Tertiary  and  Cretaceous 
rocks  of  Mississippi  and  other  Southern  States,  and  so  have  a  much 
greater  extension  in  that  direction  than  that  of  its  present  surface  dis- 
tribution.    To  the  north,  the  Cincinnati  "uplift,"  an  area  of  Silurian 
rocks  extending  from  Lake  Erie  over  Cincinnati  to  Tennessee,  forms 
the  western  boundary. 

4.  The  Michigan  coal  area,  an  isolated  area  wholly  confined  within 
the  lower  peninsula  of  Michigan. 

5.  The  Eastern  Interior  area,  covering  nearly  two  thirds  of  Illinois, 
and  parts  of  Indiana  and  Kentucky. 

6.  The  Western  Interior  area,  covering  a  large  part  of  Missouri,  and 
extending  north  into  Iowa,  and  southward,  with  interruptions,  through 
Arkansas  into  Texas,  and  westward  into  Kansas  and  Nebraska. 

The  Illinois  and  Missouri  areas  are  connected  now  only  through  the 
underlying  Subcarbonifcrous  rocks  of  the  age;  but  it  is  probable  that 
formerly  the  coal-fields  stretched  across  the  channel  of  the  Mississippi, 
and  that  the  present  separation  is  due  to  erosion  along  the  valley. 

Rocks  of  the  Carboniferous  period  extend  over  large  portions  of  the 
Rocky  Mountain  area,  but  they  are  mostly  limestones,  and  are  barren 
of  coal. 


356  DESCRIPTIONS   OF  MINERALS. 

The  extent  of  the  coal-bearing  area  of  these  Carboniferous  regions 
is  approximately  as  follows: 

Ehode  Island  area 500  square  miles. 

Alleghany  area 59,000  square  miles. 

Michigan  area 6,700  square  miles. 

Illinois,  Indiana,  West  Kentucky 47,000  square  miles. 

Missouri,  Iowa,  Kansas,  Arkansas,  Texas  78,000  square  miles. 
Nova  Scotia  and  New  Brunswick 18,000  square  miles. 

The  whole  area  in  the  United  States  is  over  190,000  square  miles, 
and  in  North  America  about  208,000.  Of  the  190,000  square  miles 
perhaps  120,000  have  workable  beds  of  coal. 

Anthracite  is  the  coal  of  Rhode  Island,  and  of  the  areas  in  Central 
Pennsylvania,  from  the  Pottsville  or  Schuylkill  coal-field  to  the  Lacka- 
wanna  field,  while  the  coal  of  Pittsburg,  and  of  all  the  great  coal- 
fields of  the  Interior  basin,  is  bituminous,  excepting  a  small  area  in 
Arkansas.  Anthracite  belongs  especially  to  regions  of  upturned  rocks, 
and  bituminous  coal  to  those  where  the  beds  are  little  disturbed.  In 
the  area  between  the  anthracite  region  of  Central  Pennsylvania  and 
the  bi'uminous  of  Western,  and  farther  south,  the  coal  is  semi-bitumin- 
ous, as  in  Broad  Top,  Pennsylvania,  and  the  Cumberland  coal-field  in 
Western  Maryland,  the  volatile  matters  yielded  by  it  being  15  to  20  per 
cent.  The  more  western  parts  of  the  anthracite  "coal-fields  aiford  the 
free-burning  anthracite,  or  semi-anthracite,  as  at  Trevorton,  Shamokin, 
and  Birch  Creek. 

The  coal  formation  of  the  Carboniferous  age  in  Europe  has  great 
thickness  of  rocks  and  coal  in  Great  Britain,  much  less  in  Spain, 
France,  and  Germany,  and  a  large  surface,  with  little  thickness  of 
coal,  in  Russia.  It  exists,  also,  and  includes  workable  coal-beds,  in 
China,  and  also  in  India,  Japan,  and  Australia;  but,  in  part,  the  forma- 
tions in  these  latter  regions  are  Permian  and  Triassic  or  Jurassic.  No 
coal  of  the  Carboniferous  era  has  yet  been  found  in  South  America, 
Africa,  or  Asiatic  Russia.  The  proportion  of  coal-beds  to  area  in  dif- 
ferent parts  of  Europe  has  been  stated  as  follows:  in  France,  l-100th  of 
the  surface;  in  Spain,  l-50th;  in  Belgium,  l-20th;  in  Great  Britain, 
l-10th.  But,  while  the  coal  area  in  Great  Britain  is  about  12,000 
square  miles,  that  of  Spain  is  4000,  that  of  France  about  2000,  and 
that  of  Belgium  518. 

The  amount  of  coal  in  exposed  Carboniferous  coal-fields  of  Great 
Britain,  within  4000  feet  of  the  surface,  and  regarded  as  workable,  as 
deduced  from  investigations  made  by  a  Royal  Commission  in  1866-71, 
was  reported  in  1878  to  be  over  90,000,000,000  tons;  more  than  a  third 
of  this  in  South  Wales;  a  fifth  in  Yorkshire  and  Derbyshire;  a  ninth 
in  Northumberland  and  Durham:  nearly  as  much  in  Scotland;  and  as 
much  also  in  Somersetshire,  combined  with  that  in  Lancashire  and 
Cheshire;  and  the  rest,  about  2-15ths  of  the  whole,  in  other  coal-areas. 
Besides  this,  it  is  estimated  that  there  are  over  56,000,000,000  tons  of 
available  coal  underneath  the  Permian  and  other  formations,  making 
in  all  about  146,500,000,000  tons,  which  is  "  1070  times  the  amount  of 
the  present  annual  output  of  125,000,000  tons." 

Mineral  coal  of  later  age  than  the  true  Carboniferous  era  occurs  in 


MINERAL  COAL.  357 

various  parts  of  the  world.  Besides  Australia  and  India,  Triassic  or 
Jurassic  coal,  of  the  bituminous  variety,  occurs  in  thick  workable 
beds  in  the  vicinity  of  Richmond,  Va.,  and  has  been  worked  in  the 
Deep  River  and  Dan  River  regions,  N.  C.  In  Scotland,  at  Brora  in 
Sutherlandshire,  there  is  a  bed  of  Oolitic  coal.  Coal  of  the  Cretaceous 
and  Tertiary  eras  constitutes  important  beds  in  various  parts  of  the 
Rocky  Mountain  region,  in  the  vicinity  of  the  Pacific  Railroad  and 
elsewhere.  Some  of  the  prominent  localities  are:  In  Utah,  at  Evans- 
ton  and  Coalville  (in  the  valley  of  Weber  River),  etc.;  in  Wyoming,  at 
Carbon,  140  miles  from  Cheyenne;  at  Hallville,  142  miles  farther 
west;  at  Black  Butte  station,  on  Bitter  Creek;  on  Bear  River,  etc.;  in 
the  Uintah  Basin,  near  Brush  Creek,  6  miles  from  Green  River;  in 
Colorado,  at  Golden  City,  15  miles  west  of  Denver,  on  Ralston  Creek, 
Coal  Creek,  S.  Boulder  Creek  and  elsewhere;  in  N.  Mexico,  at  the  Old 
Placer  Mines  in  the  San  Lazare  Mountains,  etc. ;  and  in  British  America, 
N.  of  Montana.  The  coal  is  of  the  bituminous  or  semibituminous 
kind,  part  of  it  true  brown  coal,  but  the  rest  more  correctly  referred 
to  true  bituminous  coal.  At  the  Old  Placer  Mines,  New  Mexico,  the 
coal  is  in  part  anthracite,  affording  88  to  91  per  cent,  of  fixed  carbon; 
the  region  is  one  of  upturned  and  altered  rocks,  like  the  anthracite 
region  of  Pennsylvania.  Other  similar  beds  occur  toward  the  Pacific 
coast,  the  most  valuable  of  them  in  Washington  Territory,  near  Seat- 
tle and  at  Bellingham  Bay;  also  on  Coos  Bay,  Oregon;  on  Vancouver 
and  adjacent  islands  in  British  Columbia.  Some  anthracite,  like  that 
of  N.  Mexico  in  origin,  occurs  on  the  Queen  Charlotte  Islands. 


358  SUPPLEMENT  TO   DESCRIPTIONS   OF   SPECIES. 


I.     CATALOGUE     OF    AMERICAN    LO- 
CALITIES OF  MINERALS. 

THE  following  catalogue  of  American  localities  of  minerals  is  intro- 
duced as  a  Supplement  to  the  Descriptions  of  Minerals.  Its  object  is 
to  aid  the  mineralogical  tourist  in  selecting  his  routes  and  arranging 
the  plan  of  his  journeys.  Only  important  localities,  affording  cabinet 
specimens,  are  'in  general  included;  and  the  names  of  those  minerals 
which  are  obtainable  in  good  specimens  are  distinguished  by  italics. 
When  the  name  is  not  italicized,  the  mineral  occurs  only  sparingly  or 
of  poor  quality.  When  the  specimens  to  be  procured  are  remarkably 
good,  an  exclamation-mark  (!)  is  added. 

MAINE. 

ALBANY. — Beryl!  green  and  black  tourmaline,  garnet,  feldspar,  rose 
quartz,  rutile. 

ANDOVER. — See  KUMFORD. 

AUBURN,  w.  part,  near  Minot  line. — Lepidolite,  amblygonite  (hebro- 
nite),  cassiterite,  colorless,  green,  blue,  and  black  tourmaline!  apatite 
(Mt.  Apatite). 

BATH. — Yesuvianite,  garnet,  magnetite,  graphite. 

BETHEL. — Cinnamon  garnet,  calcite,  sphene,  beryl,  pyroxene,  horn- 
blende, epidote,  graphite,  talc,  pyrite,  arsenopyrite,  magnetite. 

BiNGHAM.^Jfomw  pyrite,  galenite,  blende,  andalusite. 

BLUE  HILL  BAY. — Arsenical  iron,  molybdenite!  galenite,  apatite! 
fluorite !  black  tourmaline  (Long  Cove),  black  oxide  of  manganese 
(Osgood's  farm),  rhodonite,  bog  manganese,  wolframite. 

BOWDOIN. — Rose  quartz. 

BOWDOINHAM. — Btryl,  molybdenite. 

BRUNSWICK. — Green  mica,  garnet!  black  tourmaline!  molybdenite, 
epidote,  calcite,  muscomte,  feldspar,  beryl. 

BUCKFIELD. — Garnet  (estates  of  Waterman  and  Lowe),  muscovite! 
tourmaline  !  magnetite. 

CAMDAGE  FARM. — (Near  the  tide  mills),  molybdenite,  wolframite. 

CAMDEN. — Made,  galenite,  epidote,  black  tourmaline,  pyrite,  talc, 
magnetite. 

CANTON. — Chrysoberyl. 

CARMEL  (Penobscot  Co.). — Stibnite,  pyrite,  macle. 

CORINNA. — Pyrite,  arsenopyrite. 

DEER  ISLE. — Serpentine,  xerd-antlque,  asbestus,  diallage,  magne- 
tite. 

DEXTER. — Galenite,  pyrite,  blende,  chalcopyrite,  green  talc. 

DIXFIELD. — Native  copperas,  graphite. 

FARMINGTON.— (Norton's  Ledge),  pyrite,  graphite,  garnet,  stauro- 
lite. 

FRANKLIN  PLANTATION. — Beryl. 


CATALOGUE   OF  AMERICAN   LOCALITIES   OF   MINERALS.    359 

FREEPORT. — Rose  quartz,  garnet,  feldspar,  scapolite,  graphite,  mus- 
covite. 

FRYEBURG. — Garnet,  beryl. 

WEST  GARDINER,  along  the  Litchfield  border.     See  LITCHFIELD. 

GEORGETOWN. — (Parker's  Island),  beryl !  black  tourmaline. 

GORHAM.  — Andalusite. 

GREENWOOD.— Graphite,  black  manganese,  beryl!  arsenopyrite,  cas- 
siterite,  mica,  rose  quartz,  garnet,  corundum,  albite,  zircon,  molybden- 
ite, magnetite,  copperas. 

HEBRON,  7  m.  s.  of  Mt.  Mica  in  Paris. — Lepidolite,  amblygonite 
(hebronite),  rubellite  !  indicolite,  green  tourmaline,  damourite  (as  altered 
tourmaline),  mica,  beryl,  apatite,  albite,  chiidrenite,  cookeite,  cassiterite, 
arsenopyrite,  idocrase. 

LINNAEUS. — Hematite,  limonite,  pyrite,  bog-iron. 

LITCHFIELD, — Sodalite,  cancrinite,  elaolite,  zircon,  hydronephelite, 
spodumene,  muscovite,  pyrrhotite  (from  bowlders). 

LOVELL. — Beryl. 

LUBEC  LEAD  MINES. — Galenite,  chalcopyrite,  blende. 

MACHIASPORT. — Jasper,  epidote,  laumontite. 

MADAWASKA  SETTLEMENTS. —  Vivianite. 

MINOT. — Beryl,  smoky  quartz. 

MONMOUTH. — Actinolite,  apatite,  elceolite,  zircon,  staurolite,  plumose 
mica,  beryl,  rutile. 

MT.  ABRAHAM. — Andalusite,  staurolite. 

NORWAY. — Chrysoberyl  f  molybdenite,  beryl,  rose  quarlz,  orthoclase, 
albite,  lepidolite,  cinnamon  garnet,  triphylite  (lithiophilite),  cookeite, 
cassiterite,  amblygonite. 

ORR'S  ISLAND.— Steatite,  garnet,  andalusite. 

OXFORD — Garnet,  beryl,  apatite,  wad,  zircon,  muscovite,  orthcclase. 

PARIS,  on  Mt.  Mica . — Green  !  red  !  black,  and  blue  tourmaline  !  mica  I 
lepidolite  !  feldspar,  albite,  quartz  crystals  !  rose  quartz,  cassiterite,  am- 
blygonite, col uni bite,  zircon,  brookite,  beryl,  smoky  quartz,  spodu- 
raene,  cookeiie,  leucopyrite,  triphylite. 

PARSONSFIELD. —  Vesuvianite!  yellow  garnet,  pargasite,  adularia, 
labradorite  (cryst.),  sctipolite,  galenite,  blende,  chalcopyrite. 

PERU. — Crystallized  pyrtte,  columbite,  beryl,  spodumene,  tripbylite 
(cryst.),  chrysoberyl. 

PHIPPSBURG  —  Yellow  garnet !  manganesian  garnet,  tesumanite,  par- 
gamte,  axintie,  laumontite  !  chabazite,  an  ore  of  cerium? 

POLAND. — Vesuvianite,  smoky  quartz,  cinnamon  garnet. 

PORTLAND. — Prehnite,  actinolite,  garnet,  epidote,  amethyst,  calcite. 

POWNAL. — Black  tourmaline,  feldspar,  scapolite,  pyrite,  actinolite, 
apatite,  rose  quartz. 

RAYMOND. — Magnetite,  scapolite,  pyroxene,  lepidolite,  tremolite^orn' 
blende,  epidote,  orthoclase,  yellow  garnet,  pyrite,  vesuvianite. 

ROCKLAND. — Hematite,  tremolite,  quartz,  wad,  talc. 

RUMFORD. — On  n.  slope  of  Black  Mtn.,  tourmaline  (red),  lepidolite, 
spodumene,  cookeite,  yellow  garnet,  vesum'anite,  pyroxene,  apatite, 
scapolite,  cassiterite,  amblygonite. 

SANFORD,  York  Co. —  Vesuwanite!  albite,  calcite,  molybdenite,  epi- 
dote, black  tourmaline,  labradorite. 

SEARSMONT.  — Andalusite,  tourmaline. 


360  SUPPLEMENT  TO   DESCRIPTION'S  OF  SPECIES. 

SOUTH  BERWICK. — Chiastolite. 

STANDISH. — Columbite  !  tourmaline. 

STONEHAM. — ColumUte,  chrysoberyl,  herderite,  topaz,  mica  (curved], 
triplite. 

STOWE. — Chrysoleryl,  flbrolite. 

STREAKED  MOUNTAIN. — Beryl!  black  tourmaline,  mica,  garnet. 

THOMASTON. — Calcite,  tremolite,  hornblende,  sphene,  arsenical  iron 
(Owl's  Head),  black  manganese  (Dodge's  Mountain),  thomsonite,  talc, 
blende,  pyrite,  galenite. 

TOPSHAM. — Quartz,  galenite,  blende,  tungstite?  beryl,  apatite,  molyb- 
denite, columbite. 

UNION.— Magnetite,  bog-ore. 

WALES.— Axinite  in  bowlder,  alum,  copperas. 

WATER  VILLE  . — Crystallized  pyrite. 

WINDHAM  (near  the  bridge). — Staurolite,  spodumene,  garnet,  beryl, 
amethyst,  cyanite,  tourmaline. 

WINSLOW. — Cassiterite. 

WINTHROP. — Staurolite,  pyrite,  hornblende,  garnet,  copperas. 

WOODSTOCK.— Graphite,  hematite,  prehnite,  epidote,  caicite. 

YORK. — Beryl,  vivianite,  oxide  of  manganese. 

The  localities  of  lepidolite,  green  and  red  tourmalines,  etc.,  in  albite 
veins,  occur  in  western  Maine  along  a  S.  E.  line  from  the  Rangeley 
Lakes  to  a  point  between  Brunswick  and  Portland,  in  Rumford,  Paris, 
Norway,  Hebron,  and  Auburn,  about  40  m.  in  length. 


NEW  HAMPSHIRE. 

Ac  WORTH. — Beryl!  mica!  tourmaline,  orthoclase,  albite,  rose 
quartz,  columbite!  cyanite,  autunite. 

ALEXANDRIA.  —Muscovite. 

ALSTEAD.  —  Mica !  albite,  black  tourmaline,  molybdenite,  andalu- 
site,  Staurolite. 

AMHERST. —  Vesumanite,  yellow  garnet,  pargasite,  amethyst,  pyrox- 
ene, magnetite. 

BARTLETT. — Magnetite,  hematite,  quartz  crystals,  danalite,  limonite, 
smoky  quartz. 

BATH.— -Galenite,  chalcopyrite,  alum. 

BEDFORD — Tremolite,  epidote,  graphite,  mica,  tourmaline,  alum, 
quartz,  graphite. 

BELLOWS  FALLS. — Cyanite,  Staurolite,  prehnite. 

BENTON. — Epidote,  beryl,  magnetite. 

BERLIN. — Chalcopyrite,  pyrite,  magnetite,  hornblende. 

BRISTOL. — Graphite,  galenite. 

C  AMPTON. — Beryl ! 

CANAAN. — Gold  in  quartz  veins  and  alluvium,  garnet. 

CHARLESTOWN.— Staurolite,  andalusite,  prehnite,  cyanite. 

CONCORD. — Fibrolite. 

CORNISH. — Rutile  in  quartz!  (rare),  Staurolite,  stibnite. 

CROYDON. — Mite!  chalcopyrite,  pyrite,  pyrrhotite,  sphalerite. 

ENFIELD. — Gold,  galenite,  Staurolite,  green  quartz,  ripidolite. 

FRANCESTON.—  Soapstone,  arsenopyrite,  quartz  crystals. 


CATALOGUE   OF   AMERICAN   LOCALITIES   OF   MINERALS.    361 

FRANCONIA. — Arsenopyrite,  chalcopyrite. 

GARDNER  MTN.— Chalcopyrite,  pyrite,  galenite. 

GILMANTON.— Tremolite,  epidote,  muscovite,  tourmaline,  limonite, 
quartz  crystals. 

GOSHEN.— Graphite,  black  tourmaline. 

GRAFTON.— Muscovite  (quarried  at  Glass  Hill,  2  m.  S.  of  Orange 
Summit),  albite!  blue,  green,  and  yellow  beryls!  (1  m.  S.  of  O.  Sum- 
mit), tourmaline,  garnets,  triphylite,  apatite,  fluorite,  columbite,  mo- 
lybdenite, rhodonite. 

GRANTHAM. — Gray  staurolite  ! 

GROTON. — Arsenopyrite,  beryl,  muscovite  crystals,  orthoclase,  colum- 
bite. 

HANOVER. — Garnet,  black  tourmaline,  quartz,  cyanite,  epidote, 
anorthite,  cyanite,  zoisite. 

HAVERHILL.— Garnet  f  arsenopyrite,  native  arsenic,  galenite, 
blende,  pyrite,  chalcopyrite,  magnetite,  marcasite,  steatite. 

HEBRON.—  Beryl,  andalusite,  graphite. 

HINSDALE. — Rhodonite,  molybdenite,  indicolite,  black  tourmaline. 

JACKSON. — Drusy  quartz,  tin  ore,  arsenopyrite,  native  arsenic,  fluo- 
rite, apatite,  magnetite,  molybdenite,  wolframite,  chalcopyrite. 

JAFFREY  (Monadnock  Mt.). — Cyanite,  limonite.  . 

KEENE. — Graphite,  soapstone,  milky  quartz,  rose  quartz. 

LANDAFF. — Molybdenite,  magnetite,  pyrrhptite. 

LEBANON. — Limonite,  arsenopyrite,  galenite,  magnetite,  pyrite. 

LISBON. — Staurolite,,  garnets,  magnetite,  Jwrnblende,  ep'.dote,  zoisite, 
hematite,  arsenopyrite,  galenite,  gold,  ankerite.  Franconia  iron- 
mine,  Hornblende,  epidote,  zoisite,  hematite,  magnetite,  garnets,  arseno- 
pyrite  (danaite),  molybdenite,  prehnite,  cyanite. 

LITTLETON. — Ankerite,  gold,  bornite,  chalcopyrite,  malachite,  me- 
naccanite,  chlorite. 

LYMAN.— Gold",  arsenopyrite,  anJcerite,  dolomite,  galenite,  pyrite, 
pyrrhotite. 

LYME. — Cyanite  (N.  W.  part),  black  tourmaline,  rutile,  pyrite,  chal- 
copyrite (E.  of  E.  village),  stibnite,  molybdenite,  cassiterite,  staurolite. 

MADISON. — Galenite,  blende,  chalcopyrite,  limonite. 

MERRIMACK. — Rutile!  (in  gneiss  nodules  in  granite  vein). 

MIDDLETOWN. — Rutile,  arsenopyrite. 

MILAN. — Chalcopyrite,  galenite,  sphalerite. 

MILLSFIELD.— Beryl,  garnets. 

MONADNOCK  MOUNTAIN. — Andalusite,  hornblende,  garnet,  graph- 
ite, tourmaline,  orthoclase,  fibrolite. 

NEW  LONDON. — Beryl,  molybdenite,  muscovite. 

NEWPORT. — Molybdenite,  staurolite. 

ORANGE. — Blue  beryls!  Orange  Summit,  chrysoberyl,  muscovite 
(W.  side  of  mountain),  albite,  tourmaline,  apatite,  galenite,  limonite. 

ORFORD. — Brown  tourmaline  (obtained  with  difficulty),  steatite, 
rutile,  cyanite,  menaccanite,  garnet,  graphite,  molybdenite,  pyrrhotite, 
melaconite,  chalcopyrite,  chalcocite,  malachite,  galenite,  ripidolite. 

PIERMONT. — Micaceous  hematite,  barite,  mica,  apatite. 

PLYMOUTH. — Columbite,  beryl. 

RICHMOND. — lolite,  rutile,  steatite,  pyrite,  anthophyllite,  talc. 

RYE. — Chiastolite  (at  Boar's  Head,  in  bowlders). 


362  SUPPLEMENT  TO   DESCRIPTIONS  OF   SPECIES. 

SADDLEBACK  MT. — Black  tourmaline,  garnet,  spinel. 

SHELBURNE  — Galenite,  black  blende,  chalcopyrite,  pyrite,  pyrolusite. 

SPRINGFIELD. — Beryls  (eight  inches  diameter),  manganesian  gar- 
nets! black  tourmaline!  in  mica  schist,  albite,  mica,  rose  quartz. 

SULLIVAN. — Tourmaline  (black)  in  quartz,  beryl. 

SURRY. — Amethyst,  galenite,  tourmaline,  cyanite. 

SUTTON. — Graphite,  beryl. 

UNITY  (estate  of  James  Neal). — Chalcopyrite,  pyrite,  chlorophyllite, 
green  mica,  actinolite,  garnet,  magnetite,  tourmaline. 

WALPOLE.— Macle,  staurolite,  mica,  graphite. 

WARE. — Graphite. 

WARREN. — uhatcopyrite,  blende,  epidote,  quartz,  pyrite,  tremolite, 
galenite,  rutile,  tajc,  molybdenite,  cinnamon  stone!  pyroxene,  horn- 
blende, beryl,  cyanite,  tourmaline  (massive),  pyrite. 

WATERVILLE. — Labradorite,  chrysolite,  amethyst. 

WESTMORELAND  (south  part). — Molybdenite  !  apatite!  blue  feldspar, 
bog  manganese  (north  village),  quartz,  amethyst,  fluorite,  chalcopyrite, 
molybdite. 

WHITE  MTS.  (Notch  near  the  "  Crawford  House").— Green  fluor- 
ite, quartz  crystals,  black  tourmaline,  andalusite,  amethyst,  amazon- 
stone. 

WHITEFIELD.  — Molybdenite. 

WINCHESTER. — Pyrolusite,  rhodonite,  rhodochrosite,  magnetite, 
pyrite,  spodumene,  tourmaline. 


VEKMONT. 

ATHENS. — Steatite,  rhomb  spar,  actinolite,  garnet. 

BALTIMORE. — Serpentine,  pyrite  ! 

BARNET. —Graphite. 

BELVIDERE.— Steatite,  chlorite. 

BENNINGTON.  — Pyrolusite,  limonite. 

BERKSHIRE. — Epidote,  hematite,  magnetite. 

BETHEL. — Actinolite!  talc,  chlorite,  octahedral  iron,  rutile,  brown 
spar  in  steatite. 

BRANDON.— Pyrolusite,  psilomelane,  limonite,  lignite,  kaolinite, 
statuary  marble;  graphite,  chalcopyrite. 

BRATTLEBOROUGH. — Black  tourmaline  in  quartz,  mica,  zoisite,  ru- 
tile. actinolite,  scapolite,  spodumene,  roofing  slate. 

BRIDGEWATER. —  Talc,  dolomite,  magnetite,  steatite,  chlorite,  gold, 
native  copper,  blende,  galenite,  blue  spinel,  chalcopyrite. 

BRISTOL. — Rutile,  limonite,  manganese  ores,  magnetite. 

BROOKFIELD.  — Arsenopyrite,  pyrite. 

CABOT. — Garnet,  staurolite,  hornblende,  albite. 

CAVENDISH.  —Garnet,  serpentine,  talc,  steatite,  tourmaline,  asbestus, 
tremolite. 

CHESTER. — Asbestus,  feldspar,  chlorite,  quartz. 

CHITTENDEN.— Psilomelane,  pyrolusite,  limonite,  hematite  and 
magnetite,  galenite,  iolite. 

COLCHESTER.— Limonite,  iron  sand,  jasper,  alum. 

CORINTH.  —Chalcopyrite  (has  been  mined),  pyrrhotite,  pyrite,  rutile. 


CATALOGUE   OF  AMERICAN   LOCALITIES   OF   MINERALS.    363 

COVENTRY.— Rhodonite. 

CBAFTSBUBY.— Mica  in  concretions,  calcite,  rutile. 

DERBY. — Mica  (adamsite). 

ELY. — Chalcopyrite,  py ri  te . 

FAIR  HAVEN. — Baojing  slate,  pyrite. 

FARMING-TON.  — Andalusite, 

FLETCHEB. — Pyrite,  magnetite,  acicular  tourmaline. 

GRAFTON. — The  Grafton  steatite  quarry  is  in  Athens;  quartz,  actin- 
elite. 

GUILFOBD.— Scapolite,  rutile. 

HARTFORD.— Calcite,  pyrite!  cyanite,  quartz,  tourmaline. 

IRASBURGH. — Ehodonite,  psilomelane. 

JAY. — Chromite,  serpentine,  amianthus,  dolomite. 

LOWELL,. — Picrosmine,  amianthus,  serpentine,  cerolite,talc,chlorite. 

MABLBOBO'. — Rhomb  spar,  steatite,  garnet,  magnetite,  chlorite. 

MIDDLESEX. — Rutile  !  (exhausted). 

MONKTON. — Pyrolusite,  limonite.  feldspar. 

MOBETOWN. — Smoky  quartz!  steatite,  talc,  wad,  rutile,  serpentine. 

MOUNT  HOLLY.—  Asbestus,  chlorite. 

NEW  FANE. — Glassy  and  asbestiform  actinolite^  steatite,  green  quartz 
(called  chrysoprase  at  the  locality),  chalcedony,  drusy  quartz,  garnet, 
chromic  and  titanic  iron,  rhomb  spar,  serpentine,  rutile. 

NOBWICH.—  Actinolite,  feldspar,  brown  spar  in  talc,  cyanite,  zoisite, 
chalcopyrite,  pyrite. 

PITTSFOBD. — Limonite,  manganese  ores,  statuary  marble  ! 

PLYMOUTH.— Siderite,  magnetite,  hematite,  gold,  galenite. 

PUTNEY. — Fluorite,  limonite.  rutile  andzoisitein  bowlders,  staurolite. 

READING. — Glassy  acliriolite  in  talc. 

READSBOBO'.— Glassy  actinolite,  steatite,  hematite. 

ROCHESTEB. — Rutile,  hematite  cryst.,  magnetite  in  chlorite  slate. 

ROCKINGHAM  (Bellows  Falls).—  Cyanite,  indicolite,  feldspar,  tour- 
maline, fluorite,  calcite,  prehnite,  staurolite. 

ROXBUBY. — Dolomite,  talc,  serpentine,  asbestus,  quartz. 

RUTLAND. — Magnetite,  white  marble,  hematite,  serpentine. 

SHARON. — Quartz  crystals,  cyanite. 

SHOREHAM. — Pyrite,  black  marble,  calcite. 

STRAFFORD.— Magnetite  and  chalcopyrite  (has  been  worked),  native 
copper,  hornblende,  copperas. 

THETFOBD. — Blende,  galenite,  cyanite,  chrysolite  in  basalt,  pynho 
tite.  feldspar,  roofing  slate,  steatite,  garnet. 

TOWNSHEND. — Actinolite,  black  mica,  talc,  steatite,  feldspar. 

TBOY. — Magnetite,  talc,  serpentine,  picrosmine,  amianthus,  steatite, 
one  mile  southeast  of  village  of  South  Troy,  on  the  farm  of  Mr. 
Pierce,  east  side  of  Missisco,  chromite,  zaratite. 

VERSHIRE. — Pyrite,  chalcopyrite,  tourmaline,  arsenopyrite,  quartz. 

WABDSBOBO'.— Zoisite,  tourmaline,  tremolite,  hematite. 

WABBEN. — Actinolite,  magnetite,  wad,  serpentine. 

WATEBBUBY. — Arsenopyrite,  chalcopyrite,  rutile,  quartz,  serpen- 
tine. 

WATERVTLLE.— Steatite,  actinolite,  talc. 

WEATHERSFIELD. — Steatite,  hematite,  pyrite,  tremolite. 

'WESTFIELD. — Steatite,  chromite,  serpentine, 


364  SUPPLEMENT  TO   DESCRIPTIONS   OF   SPECIES. 

WESTMINSTER.— Zoisite  in  bowlders. 

WINDHAM.— Glassy  actinolite,  steatite,  garnet,  serpentine. 

WOODSTOCK. — Quartz  crystals,  garnet,  zoisite. 

MASSACHUSETTS. 

ATHOL. — Allanite,  fibrolite  (?),  epidote!  babingtonite  ? 

AUBURN. — Masonite. 

T$KKKE..—llutile!  mica,  pyrite,  beryl,  feldspar,  garnet. 

GREAT  BARRINGTON. — Tremolite. 

BEDFORD. — Garnet. 

BELCHERTON.  —-Allanite. 

BERNARDSTON. — Magnetite  at  loc.  of  crinoidal  limestone. 

BEVERLY.— Columbite,  green  feldspar,  cassiterite. 

BLANFORD. — Serpentine,  anthophyllite,  actinolite!  chromite,  cyanite, 
rose  quartz  in  bowlders. 

BOLTON. — Scapolite!  petalile,  sphene,  pyroxene,  nuttalite,  diopside. 
boltonite,  apatite,  magnesite,  rhomb  spar,  allanite,  yttrocente!  spinel. 

BOXBOROUGH. — Scapnlite.  spinel,  garnet,  augite,  actinolite,  apatite. 

BRIMFIELD  (road  leading  to  Warren). — Mite,  andalusite,  adularia, 
molybdenite,  mica,  garnet. 

CARLISLE. — Tourmaline,  garnet !  scapolite.  actinolite. 

CHARLESTOWN. — Prehnite,  laumontite,  stilbite,  chabazite,  quartz 
crystals,  melanolite. 

CHELMSFORD. — Scapolite  (chelmsfordite),  cliondrodite,  blue  spinel, 
amianthus  !  rose  quartz. 

CHESTER. — Hornblende,  scapolite,  zoisite,  spodumene,  indicolite, 
apatite,  magnetite,  chromite,  stilbite,  heulandite,  analcite,  and  cha- 
bazite.  At  the  Emery  Mine,  Chester  Factories. — Corundum,  marga- 
rite,  diaspore,  epidote,  corundophilite,  chloritoid,  tourmaline,  menac- 
canite,  rutile,  biotite,  cyanite,  arnesite. 

CHESTERFIELD. — Blue,  green,  and  red  tourmaline,  cleavelandite 
(albite),  lepidolite,  smoky  quartz,  microlite,  spodumene,  cyanite,  apatite, 
beryl,  garnet,  quartz  crystals,  staurolite,  cassiterite,  columbite,  zoisite, 
uranite,  brookite  (eumanite),  scheelite,  anthophyllite,  bornite. 

CONWAY. — Pyrolusite,  fluorite,  zoisite,  rutile  !  native  alum,  gale- 
nite. 

CUMMINGTON. — Rhodonite  !  cummingtonite  (hornblende),  marcasite, 
garnet. 

DEERFIELD. — Chabazite,  heulandite,  stilbite,  datolite,  prehnite, 
natrolite,  analcite,  calcite,  fluorite,  diabantite,  saponite,  amethyst, 
carnelian,  chalcedony,  agate,  pyrite,  malachite. 

FITCHBURG  (Pearl  Hill). — Beryl,  staurolite  !  garnets,  molybdenite. 

FOXBOROUGH. — Pi/rite,  anthracite. 

FRANKLIN.  — Amethyst. 

GLOUCESTER. — Danalite. 

GOSHEN. — Mica,  albite,  spodumene !  blue  and  green  tourmaline, 
beryl,  zoisite,  smoky  quartz,  columbite,  tin  ore,  galenite,  beryl  (goshen- 
ite),  cymatolite  (mixture  of  albite  and  muscovite). 

GREENFIELD  (in  sandstone  quarry,  %  m.  E.  of  village). — Allophane. 

HATFIELD. — Barite,  galenite,  blende,  chalcopyrite,  quartz  crystals. 


CATALOGUE   OF   AMERICAN    LOCALITIES   OF   MINERALS.    365 

HAWLEY. — Micaceous  iron,  massive  pyrite,  magnetite,  zoisite. 

HEATH. — Pyrite,  zoisite. 

HINSDALE. — Limonite,  apatite,  zoisite. 

HUBBARDSTON.—  Massive  pyrite. 

HUNTINGTON  (name  changed  from  Norwich). — Apatite!  black  tour- 
maline, beryl,  spodumene  !  triphylite  (altered),  blende,  quartz  crystals, 
cassiterite. 

LANCASTER. — Cyanite,  chiastolite!  apatite,  staurolite,  pinite,  anda- 
lusite. 

LEE. — Tremolite,  sphene,  chondrodite  in  South  Lee. 

LEVERETT. — Barite,  galenite,  blende,  chalcopyrite. 

LEYDEN. — Zoisite,  rutile. 

MARBLEHEAD. — In  zircon  syenyte,  sodalite,  elseolite. 

MARTHA'S  VINEYARD.— Limonite,  amber,  radiated  pyrite. 

MENDON. — Mica  !  chlorite. 

MIDDLEFIELD. — Olassy  actinolite,  rhomb  spar,  steatite,  serpentine, 
feldspar,  drusy  quartz,  apatite,  zoisite,  nacrite,  chalcedony,  talc! 
deweylite. 

MILBURY. —  Vermiculite. 

NEW  BRAINTREE. — Black  tourmaline. 

NEWBURY. — Serpentine,  chrysotile,  epidote,  massive  garnet,  siderite. 

NEWBURYPORT. — Serpentine,  nemalite,  uranite. — Argentiferous  ga- 
lenite, tetrahedrite,  chalcopyrite,  pyrargyrite,  etc. 

NORTHFIELD.— Columbite,  fibrolite,  cyanite. 

NORWICH.— See  HUNTINGTON. 

PALMER  (Three  Rivers). — feldspar,  prehnite,  calcite. 

PELHAM. — Asbestus,  serpentine,  quartz  crystals,  beryl,  molybdenite, 
green  hornstone,  epidote,  amethyst,  corundum,  vermiculite  (pelhamite). 

PLAINFIELD. — Cummingtonite,  prolusite,  rhodonite. 

RICHMOND. — Limonite,  gibbsite!  allophane. 

ROCKPORT  (near  the  extremity  of  C.  Ami).—Da?ialite,  cryophyllite, 
annite,  cyrtolite  (altered  zircon),  amazonstone,  fergusonite,  lepidome- 
lane,  green  and  white  orthoclase. 

ROWE. — Epidote,  talc  ;  at  Davis  mine,  pyrite,  chalcopyrite,  gah- 
nite,  zoisite. 

SOUTH  ROYALSTON. — Beryl !  (now  obtained  with  dimculty),  mica  ! 
feldspar  !  allanite.  Four  miles  beyond  old  loc.,  on  farm  of  Solomon 
Hey  wood,  mica!  beryl !  feldxpai- !  menaccanite. 

RUSSEL. — Garnet!  mica,  serpentine,  beryl,  galenite,  chalcopyrite. 

SALEM. — Cancrinite,  sodalite,  elaBolite,  zircon. 

SHEFFIELD. — Asbestus,  pyrite,  native  alum,  pyrolusite,  rutile. 

SHELBURNE  . — Rutile . 

SHUTESBURY  (east  of  Locke's  Pond). — Molybdenite. 

SOUTHAMPTON.— Galenite,  cerussite,  anglesite,  iculfenite,  fluorite, 
barlte,  pyrite,  chalcopyrite,  blende,  phosgenite,  pyromorphite,  stolzite, 
chrysocolla. 

STERLING. — Spodumene.  chiastolite,  siderite,  arsenopyrite,  blende, 
galenite,  chalcopyrite,  pyrite,  sterlingite  (darnourite). 

STONEHAM.  — Nephrite. 

STURBRIDGE. — Graphite,  garnet,  apatite,  bog-ore. 

SWAMPSCOT.— Or/fo'te,  feldspar. 

TAUNTON  (one  mile  south). — Paracolumbite  (titanic  iron). 


3G6  SUPPLEMENT  TO   DESCRIPTIONS   OF   SPECIES. 

TURNER'S  FALLS  (Conn.  River). — Chalcopyrite,  prehnite,  chlorite, 
siderite,  malachite. 

TYRINGHAM  and  on  borders  of  OTIS. — Pyroxene,  scapolite,  chondro- 
dite,  sphene,  hornblende,  splierostilbite. 

WARWICK. — Massive  garnet,  radiated  black  tourmaline,  magnetite, 
beryl,  epidote. 

WASHINGTON. — Graphite. 

WESTFIELD. — Schiller  spar  (diallage),  serpentine,  steatite,  cyanite, 
scapolite,  actinolite. 

WESTFORD. — Andalnsite  ! 

WEST  HAMPTON. — Galenite,  argentine,  pseudomorphous  quartz. 

WEST  STOCKBRIDGE. — Limonile,  fibrous  pyrolusite,  siderite. 

WlLLIAMSBURG. — JT 

smoky 

WINDSOR. 

WORCESTER.— Arsenopyrite,  idocrase,  pyroxene,  garnet,  amianthus, 
bucholzite,  siderite,  galenite. 

WORTHINGTON. — Cyanite. 

ZOAR. — Bitter  spar,  talc. 


IT  DTOCKBRIDGE. — Limomie,  norous  pyrolusite,  siaente. 
LIAMSBURG. — Zoisile,  pseudomorphous  quartz,  apatite,  rose  and 
quartz,  galenite,  pyrolusite,  chalcopyrite. 
Dso-R.-Zoi.nfe,  actinolite,  rutile! 


RHODE  ISLAND. 

BRISTOL  . — A  methyst. 

CRANSTON. — Actinolite  in  talc,  graphite,  cyanite,  mica,  melanterite. 

CUMBERLAND. — Manganese,  epidote,  aclinolite,  garnet,  titaniferous 
iron,  magnetite,  hematite,  chalcopyrite,  bornite,  malachite,  azurite, 
calcite,  apatite,  feldspar,  zoisite,  mica,  quartz  crystals,  ilvaite. 

DIAMOND  HILL. — Quartz  crystals,  hematite. 

FOSTER. — Gya  nite,  hematite. 

GLOUCESTER. — Magnetite  in  chlorite  slate,  feldspar. 

JOHNSTON. — Talc,  brown,  spar,  calcite,  garnet,  epidote,  pyrite,  he- 
matite, magnetite,  chalcopyrite,  malachite,  azurite. 

NATIC.— See  WARWICK. 

NEWPORT. — Serpentine,  quartz  crystals. 

PORTSMOUTH. — Anthracite,  graphite,  asbestus,  pyrite,  chalcopyrite. 

SMITHFIELD. — Dolomite,  calcite,  bitter  spar,  siderite,  nacrite,  serpen- 
tine (bowenite),  tremolite,  asbestus,  quartz,  magnetite  in  chlorite 
schist,  talc!  octahedrite,  feldspar,  beryl. 

VALLEY  FALLS.— Graphite,  pyrite,  hematite. 

WARWICK  (Natic  village). — Masonite,  garnet,  graphite,  bog-ore. 

WESTERLY.  — Menaccanite. 

WOONSOCKET. — Cyanite. 


CONNECTICUT. 

BERLIN. — Barite,  datolite,  blende,  quartz  crystals. 

BOLTON.  — Staurolite,  cbalcopyrite. 

BRANCHVTLLE. — Pyroxene,  garnet.  Albite,  microclme^ 
spodumenef  cymatolite,  margarodite   (curved),  eosphorite,  triploidite, 
reddingite,  dickinsonite,  lithiophilite,  rhodochrosite,  fairfieldite,  a/pa 


CATALOGUE   OF  AMERICAN"   LOCALITIES   OF  MINERALS.    367 

tite,  microlite,  columbite  !  garnet,  pyrite,  tourmaline,  staurplite,  urani- 
nite,  torbernite,  autunite,  vivianite,  eucryptite,  chabazite,  stilbite, 
heulandite. 

BRISTOL. — Chalcocite,  chalcopyrite,  barite,  bornite,  allophane,  pyro- 
morphite,  calcite,  malachite,  galenite,  quartz. 

BROOKFIELD. — Galenite,  calamine,  blende,  spodumene,  pyrrhotite, 
chal  copy  rite. 

CANAAN. — Tremolite  and  white  pyroxene!  in  dolomite,  canaanite 
(massive  pyroxene). 

CHATHAM. — Arsenopyrite,  smaltite,  cloanthite  (chathamite),  scoro- 
dite,  niccolite,  beryl,  erythrite. 

CHESHIRE. — Barite  f  chalcocite,  bornite,  malachite,  kaolin,  natro- 
lite,  prehnite,  chabazite,  datolite. 

CHESTER. — tiillimanite!  zircon,  epidote. 

CORNWALL. — Graphite,  pyroxene,  actinolite,  sphene,  scapolite. 

D ANBURY.—  Danbu rite  with  oligodase  (formerly),  brown  tourmaline, 
orthoclase,  pyroxene,  parathorite. 

FARMINGTON.— Prehnite,  chabazite,  agate,  native  copper,  diabantite. 

RADDAM.—Chrysoberylf  (not  accessible),  beryl,  epidote,  tourmaline, 
orthoclase,  garnet,  iolite!  chlorophyllite  f  oligoclase,  automolite,  mag- 
netite, adularia,  apatite,  columbite!  (hermannolite),  zircon  (calypto- 
lite),  mica,  pyrite,  marcasite,  molybdenite,  allanite,  bismuth  ochre, 
bismutite. 

HADLYME.— Chabazite  and  stilbite  in  gneiss. 

HARTFORD.— Datolite  (Eocky  Hill  quarry). 

LITCHFIELD. — Cyanite  with  corundum,  apatite,  and  andalusite,  me- 
ft<^camte(washingtonite),  chalcopyrite,  diaspore,  niccoliferous  pyrrho- 
tite, margarodite,  staurolite. 

LYME.— Garnet,  sunstone,  microcline. 

MERIDEN. — Datolite  (greenish),  diabantite. 

MIDDLEFIELD  FALLS.  — Datolite,  chlorite,  etc.,  in  amygdaloid. 

MIDDLETOWN. — Mica,  albite,  feldspar,  columbifef  prehnite,  garnet, 
beryl,  topaz,  uranite,  apatite,  pitchblende,  lepidolite  with  green  and 
red  tourmaline ;  at  lead-mine  formerly  galenite,  chalcopyrite,  blende, 
quartz,  calcite,  fluorite,  pyrite  sometimes  capillary. 

MILPORD. — Sahlite,  pyroxene,  asbestus,  verd -antique  marble. 

INlsw  HAVEN. — Serpentine,  sahlite,  stilbite,  laumontite. 

NEWTOWN. — Cyanite,  diaspore,  rutile,  damourite. 

NORWICH. — Sillimanite,  monazite!  iolite,  corundum,  feldspar. 

PORTLAND.— Orthoclase,  albite,  muscovite,  biotite,  beryl,  tourmaline, 
columbite,  apatite  ;  at  Pelton's  feldspar  quarry,  monazite. 

PLYMOUTH. — Galenite,  heulandite,  fluorite,  chloryphyllite  !  garnet. 

ROARING  BROOK  (Cheshire).—  Datolite!  calcite,  prehnite,  saponite. 

ROXBURY. — Siderite,  blende,  pyrite!  galenite,  quartz,  chalcopyrite, 
arsenopyrite,  limonite. 

SALISBURY. — Limonite,  pyrolusite,  manganite,  triplite,  turgite,  sco- 
villite,  staurolite. 

SEYMOUR. — Arsenopyrite,  pyrite. 

SIMSBURY.— Chalcocite,  green  malachite. 

SOUTHBURY. — Rose  quartz,  laumonlite,  prehnite,  calcite,  barite. 

SOUTHINGTON. — Barite,  datolite,  asteriated  quartz  crystals,  diaban- 
tite. 


368         SUPPLEMENT  TO   DESCRIPTIONS   OF   SPECIES. 

STAFFORD. — Massive  pyrite,  alum,  copperas. 

TARIFFVILLE.  —Datolite  ! 

TRUMBULL  and  MONROE. — Chlorophane,  topaz  (vein  not  open),  beryl, 
diaspore,  pyrrhotite,  pyrite,  scheelite,  wolframite  (pseudomorph  of 
scheelite),  native  bismuth,  tungstic  acid,  siderite,  arsenopyrite,  argen- 
tiferous galenite,  blende,  scapolite,  tourmaline,  garnet,  albite,  augite, 
graphic  tellurium  (?),  margarodite. 

WASHINGTON. — Tripohte,  menaccanite!  (washingtonite  of  Shep- 
ard),  rhodochrosite,  natrolite,  andalusite  (New  Preston),  cyanite. 

WATERTOWN,  near  the  Naugatuck. — White  sahlite,  inonazite. 

WEST  FARMS. — Asbestus. 

WILLIMANTIC. — Topaz,  monazite,  ripidolite. 

NEW  YORK. 

ALBANY  CO.— BETHLEHEM.— Calcite,  stalactite,  calcareous  sin- 
ter, snowy  gypsum. 

COEYMAN'S  LANDING. — Gypsum,  epsom  salt,  quartz  crystals  at 
Crystal  Hill,  3  m.  S.  of  Albany. 

WATERVLIET. — Quartz  crystals,  yellow  drusy  quartz. 

CAYUGA  CO.— AUBURN.— Celestite,  calcite,  fluor  spar,  ep- 
somite. 

SPRINGPORT. — At  Thompson's  plaster-beds,  sulphur,  sclenite. 

UNION  SPRINGS. — Selenite,  gypsum. 

CLINTON  CO. — ARNOLD  IRON  MINE. — Magnetite,  epidote,  mo- 
lybdenite. 

FINCH  ORE  BED. — Calcite,  green  and  purple  fluor. 

PLATTSBUKG. — Nugget  of  platinum  in  drift. 

COLUMBIA  CO.— ANCRAM.— Lead-mine,  galenite,  blende,  wul- 
feuite,  chalcopyrite. 

CANAAN. — Chalcocite,  chalcopyrite,  argentiferous  galenite. 

COPAKE. — Limonite  (large  ore- beds). 

HUDSON. — Stlenite. 

NEW  LEBANON. — Nitrogen  springs,  epsom  salt,  brown  spar,  wad, 
siderite. 

DUTCHESS  CO.— AMENIA.— Dolomite,  limonite.  turgite,  siderite. 

DOVER.— Dolomite,  tremolite,  garnet,  (Foss  ore-bed)  Umonile, 
staurolite. 

FISHKILL. — Dolomite  ;  near  Peckville,  talc,  asbestus,  graphite, 
hornblende,  augite,  actinolite,  hydrous  anthophyllite,  limonite. 

NORTH  EAST. — Chalcocite,  chalcopyrite,  galenite,  blende. 

UNION  VALE. — At  the  Clove  mine,  gibbsite,  limonite. 

ESSEX  CO. — ALEXANDRIA. — Kirby's  graphite  mine,  graphite, 
pyroxene,  scapolite,  sphene. 

CROWN  POINT. — Apatite  (eupyrchrcite  of  Emmons),  brown  tourma- 
line! in  the  apatite,  chlorite,  quartz  crystals,  calcite,  pyrite;  S.  of 
J.  C.  Hammond's  house,  garnet,  scapolite,  chalcopyrite,  aventurine 
feldspar,  zircon,  magnetite  (Peru),  epidote,  mica. 

KEENE. — Scapolite. 

LEWIS. — Tab  alar  spar,  colophonite,  garnet,  labradorite,  Jiornblende, 
actinolite;  10  m.  S.  of  Keeseville,  arsenopyrite. 

LONG  POND. — Apatite,  garnet,  pyroxene,  idocrase,  coccolile!  scapo- 
lite,  magnetite,  blue  calcite. 


CATALOGUE   OF  AMERICAN   LOCALITIES   OF   MINERALS.    369 

MclNTYRE. — Labradorite,  garnet,  magnetite. 

MORIAH,  at  Saudford  Ore  Bed. — Magnetite,  apatite,  allanite!  lan- 
thanite,  actinolite,  and  feldspar;  at  Fisher  Ore  Bed,  magnetite,  feld- 
spar, quartz;  at  Hall  Ore  Bed,  or  "  New  Ore  bed,"  magnetite,  zircons; 
on  Mill  brook,  calcite,  pyroxene,  hornblende,  albite;  in  the  town  of 
IVIoriah,  magnetite,  black  mica;  Barton  Hill  Ore-bed,  albite. 

NEWCOMB. — Labradonte,  feldspar,  magnetite,  hypersthene. 

PORT  HENRY. — Brown  tourmaline,  black  tourmaline  enclosing  or- 
thoclase,  mica,  rose  quartz,  serpentine,  green  and  black  pyroxene,  horn- 
blende, cryst.  pyrite,  graphite,  wollastonite,  pyrrhotite,  adularia ; 
plilogopite!  at  Cheever  Ore  Bed,  with  magnetite  and  serpentine;  in, 
Champlain  iron  region,  uranothorite. 

ROGER'S  ROCK. — Graphite,  wollastonite,  garnet,  feldspar,  adularia, 
•pyroxene,  sphene,  coccolite. 

SCHROON. — Calcite,  pyroxene,  chondrodite. 

TICONDEROGA. — Graphite !  pyroxene,  sahlite,  sphene,  black  tour- 
maline, cacoxenite?  (Mt.  Defiance). 

WESTPORT. — Lnbradorite,  prehnite,  magnetite. 

WILLSBORO'. —  Wollastonite,  colophonite,  garnet,  green  coccolite, 
hornblende. 

GREENE  CO.— DIAMOND  HILL.— Quartz  crystals. 

HERKIMER  CO.—  FAIRFIELD.—  Quartz  crystals,  fetid  barite. 

LITTLE  FALLS. — Quartz  crystals!  barite,  calcite,  smoky  quartz; 
I  m.  S.  of  Little  Falls,  calcite,  brown  spar,  feldspar. 

MIDDLEVILLE. — Quartz  crystals!  calcite,  brown  and  pearl  spar. 

NEWPORT. — Quartz  crystals. 

SALISBURY.— Quartz  crystals!  blende,  galenite,  pyrite,  chalcopy- 
rite. 

STARK. — Fibrous  celestite,  gypsum. 

JEFFERSON  CO.— ADAMS.— Fluor,  calc  tufa,  barite. 

ALEXANDRIA. — On  S.  E.  bank  of  Muscolonge  Lake,  fluorite  (ex- 
hausted), phlogopite,  chalcopyrite,  apatite;  on  High  Island,  in  the  St. 
Lawrence  River,  feldspar,  tourmaline,  hornblende,  orthoclase,  celes- 
tite. 

ANTWERP. — Sterling  iron-mine,  hematite,  chalcodite,  siderite,  mil- 
lerite,  red  hematite,  crystallized  quartz,  yellow  aragonite,  niccoliferous 
pyrite,  quartz  crystals,  pyrite;  at  Oxbow,  calcite!  porous  coralloidal 
heavy  spar;  near  Vrooman's  lake,  calcite!  vesuvianite,  phlogopite! 
pyroxene,  sphene,  fluorite,  pyrite,  chalcopyrite  ;  &\so  feldspar,  bog-iron 
ore,  scapolite  (farm  of  Eggleson),  serpentine,  tourmaline  (yellow, 
rare). 

BROWNSVILLE. — Celestite,  calcite  (4  m.  from  Watertown). 

NATURAL  BRIDGE. — Gteseckile!  steatite  pseudomorphous  after  py- 
roxene, apatite. 

NEW  CONNECTICUT. — Sphene,  brown  phlogopite. 

OMAR. — Beryl,  feldspar,  hematite. 

PHILADELPHIA. — Garnets  on  Indian  River,  in  the  village. 

PILLAR  POINT. — Massive  barite  (exhausted). 

THERESA. — Fluorite,  calcite,  hematite,  hornblende,  quartz  crystal, 
serpentine  (associated  with  hemaiite),  celestite,  strontianite. 

WATERTOWN. —  Tremolite,  agaric  mineral,  calc  tufa,  celestite. 

WILNA. — One  mile  N.  of  Natural  Bridge,  calcite. 
24 


370          SUPPLEMENT  TO   DESCRIPTIONS   OF   SPECIES. 

LEWIS  CO. — DIANA  (localities  mostly  near  junction  of  crystal- 
line and  sedimentary  rocks,  and  2  m.  from  Natural  Bridge). — Scapo- 
lite!  wollastonite,  green  coccolite,  feldspar,  tremolite,  pyroxene! 
sphene!  mica,  quartz  crystals,  pyrite,  pyrrhotite,  blue  calcite,  serpen- 
tine, rensselaerite,  zircon,  graphite,  chlorite,  hematite,  bog-ore, 
apatite. 

GREIG. — Magnetite,  pyrite. 

LOWVILLE. — Calcite,  fluorite,  pyrite,  galenite,  blende,  calc  tufa. 

MARTINSBURGH. — Wad,  galenite,  etc.  (formerly),  calcite. 

MONROE  CO. — ROCHESTER. — Pearl  spar,  calcite,  snowy  gyp- 
sum, fluor,  celestite,  galenite,  blende,  barite,  hornstone. 

MONTGOMERY  CO.—  PALATINE.— Quartz  crystals,  drusy  quartz, 
anthracite,  hornstone,  agate,  garnet. 

ROOT. — Drusy  quartz,  blende,  barite,  stalactite,  galenite,  pyrite. 

NEW  YORK  CO.—  KINGSBRIDGE.— Tremolite,  pyroxene,  mica, 
tourmaline,  pyrite. 

NEW  YORK.—  Serpentine,  amianthus,  actinolite,  pyroxene,  hydrous 
anthophyllite,  garnet,  staurolite,  molybdenite,  graphite,  chlorite, 
beryl,  jasper,  necronile,  feldspar.  In  the  excavations  for  the  4th 
Avenue  tunnel,  1875,  harmotome,  stilbite,  chabazite,  heulandite,  etc. 

NI AG A R A.  CO.  —  LEWISTON. — Epsomite. 

LOCKPORT,— Celestite,  calcite,  selenite,  anhydrite,  fluorite,  dolomite, 
sphalerite. 

NIAGARA  FALLS. — Calcite,  fluorite,  blende,  dolomite. 

ONEIDA  CO. — BOONVILLE. — Calcite,  zoollastonite,  coccolite. 

CLINTON. — Blende,  lenticular  hematite  iu  the  Clinton  group,  stron- 
tianite,  celestite,  the  former  covering  the  latter. 

ONON  D  AG  A.  CO. — CAMILLUS. — Selenite  and  fibrous  gypsum. 

SYRACUSE. — Serpentine,  celesiite,  seleuite,  barite. 

ORANGE  CO. — CORNWALL  — Zircon,  chondrodite,  hornblende, 
spinel,  feldspar,  epidote,  hudsonite,  menaccanite,  serpentine,  coccolite. 

DEER  PARK.— Cryst.  pyrite,  galenite. 

MONROE. — Mica!  sphene  f  garnet,  colophonite,  epidote,  chondrodite, 
allanife,  bucholzite,  brown  spar,  spinel,  hornblende,  talc,  menaccanite, 
pyrrhotite,  pyrite,  chromitc,  graphite,  rastolyte,  moronolite  ;  Wilks 
and  O'Neill  Mine,  aragonite,  magnetite,  dimagnetite  (pseud.?),  jen- 
kinsite,  asbestus.  serpentine,  mica,  hortonolite  ;  Two  PONDS,  pyroxene  ! 
chondrodite,  hornblende,  scapolite !  zircon,  sphene,  apatite ;  GREEN- 
WOOD FURNACE,  chondrodite,  pyroxene!  mica,  hornblende,  spinel, 
scapolite,  biotite!  menaccanite. 

FOREST  OF  DEAN. — Pyroxene,  spinel,  zircon,  scapolite,  hornblende. 

TOWN  OF  WARWICK,  WARWICK  VILLAGE. — Spinel!  zircon,  ser- 
pentine! brown  spar,  pyroxene!  Jwrnblende  !  pseud  amorphous  steatite, 
feldspar!  (Rock  Hill),  menaccanite,  clintonite,  tourmaline  (R.  H.), 
rutile,  sphene,  molybdenite,  arsenopyrite,  marcasite,  pyrite,  yellow 
iron  sinter,  quartz,  jasper,  mica,  coccolite. 

AMITY. — Spinel!  garnet,  scapolite,  hornblende,  vexumanite,  epidote! 
clintonite!  magnetite,  tourmaline,  warwickite,  apatite,  chondrodite, 
talc!  pyroxene!  rutile,  menaccanite,  zircon,  corundum,  feldspar, 
sphene,  calcite,  serpentine,  schiller  spar  (?),  silvery  mica. 

EDENVILLE. — Apatite,  chondrodite!  hair-brown  Jwrnblende!  tremo- 
lite,  spinel,  tourmaline,  warwickite,  pyroxene,  sphene,  mica,  feldspar, 


CATALOGUE   OF  AMERICAN   LOCALITIES  OF  MINERALS.    371 

arsenopyrite,  orpiment,  ruffle,  menaccanite,  scorodite,  chalcopyrite, 
leucopyrite  (or  lollingite),  allanite. 

WEST  POINT. — 1'eldspar,  mica,  scapolite,  sphene,  hornblende,  al- 
lanite. 

PUTNAM  CO.— BREWSTER,  Tilly  Foster  Iron  Mine.— Chondro- 
dite !  magnetite,  dolomite,  serpentine  pseudomorplis,  brucite.  emtatite, 
ripidolite,  biotite,  actinolite,  pyrrhotite,  fiuorite,  albite,  epidote,  sphene, 
apophyllite. 

ANTHONY'S  NOSE,  at  top,  pyrite,  pyrrhotite,  pyroxene,  hornblende, 
magnetite. 

CARMEL  (Brown's  quarry). — Anthophyllite,  arsenopyrite,  epidote. 

COLD  SPRING. — Sphene,  epidote. 

PATTERSON. —  White  pyroxene  !  calcite,  asbestus,  tremolite,  dolomite, 
massive  pyrite. 

PHILLIPSTOWN. — Tremolite,  amianthus,  serpentine,  sphene,  diopside, 
green  coccolite,  hornblende,  scapolite,  stilbite,  mica,  laumontite,  gur- 
hofite,  calcite,  magnetite,  chromite. 

PHILLIPS  Ore  Bed. — Hyalite,  actinolite.  massive  pyrite. 

RICHMOND  CO.— ROSSVILLE.— Lignite,  cryst.  pyrite. 

QUARANTINE. — Asbestus,  amianthus,  aragonite,  dolomite,  gurhofite, 
brucite,  serpentine,  talc,  magnesite. 

ROCKLAND  CO.— CALDWELL.— Calcite. 

LADENTOWN. — Zircon,  malachite,  cuprite. 

PIERMONT. — Datolite,  stilbite,  apophyllite,  pectolite,  prehnite, 
thomsonite,  calcite,  chabazite. 

ST.  LAWRENCE  CO.— CANTON.— Massive  pyrite,  calcile,  brown 
tourmaline,  sphene,  serpentine,  talc,  rensselaeriie,  pyroxene,  hematite, 
chalcopyrite. 

DE  KALB. — Hornblende,  barite,  fluorite,  tremolite,  tourmaline,  white 
tourmaline,  blende,  graphite,  pyroxene,  diopside  quartz  (spongy), 
serpentine. 

EDWARDS. — Brown  and  silvery  mica  !  scapolite,  apatite,  quartz  crys- 
tals, actinolite,  tremolite  !  hematite,  serpentine,  magnetite. 

FINE. — Black  mica,  hornblende. 

FOWLER. — Barite,  quartz  crystals!  hematite,  blende,  galenite,  tremo- 
lite, chalcedony,  bog-ore,  satin  spar  (assoc.  with  serpentine),  pyrite, 
chalcopyrite,  actinolite,  rensselaerite  (near  Somerville). 

GOUVERNEUR. — Calcite !  serpentine!  hornblende!  scapolite!  ortho- 
clase,  tourmaline!  idocrase  (1  m.  8.  of  G.),  pyroxene,  malacolite, 
apatite,  rensselaerite,  serpentine,  sphene,  fluorite,  barite  (farm  of  Judge 
Dodge),  black  mica,  phlogopite,  tremolile  !  asbestus,  hematite,  graph- 
ite, vesuvianite  (near  Somerville  in  serpentine),  spinel,  houghite, 
scapolite,  phloyopite.  dolomite ;  £  m.  W.  of  Somerville,  cJiondrodite, 
spinel ;  2  m.  N.  of  Somerville,  apatite,  pyrite,  brown  tourmaline!  f 

HAMMOND. — Apatite!  zircon!  (farm  of  Mr.  Hardy),  orthodase 
(loxocase),  pargasite,  barite,  pyrite,  purple  fluorite,  tremolite,  phlogo- 
pite. 

HERMON. — Quartz  crystals,  hematite,  siderite,  pargasite,  pyroxene, 
serpentine,  tourmaline,  bog-iron  ore. 

MACOMB. — Blende,  mica,  galenite  (on  land  of  James  Averill), 
sphene,  peristerite. 


372  SUPPLEMENT  TO   DESCRIPTIONS   OF   SPECIES. 

MINERAL  POINT,  Morristown.— Fluorite,  blende,  galenite,  phlugo- 
pite  (Pope's  Mills),  barite. 

OGDENSBURGH. — Labradorite. 

PIERREPONT. — Tourmaline,  sphene,  scapolite,  hornblende,  pyr- 
oxene. 

PITCAIRN. — Satin  spar,  associated  with  serpentine,  titanite. 

POTSDAM. — Hornblende!;  eight  miles  from  Potsdam,  on  road  to 
Pierrepont,  feldspar,  tourmaline,  black  mica,  hornblende. 

ROSSIE  (Iron  Mines).  —Barite,  hematite,  coralloidal  aragonite  (near 
Somerville),  quartz,  pyrite,  pearl  spar ;  ROSSIE  Lead  Mine,  calcite, 
gulenite,  pyrite,  celestite,  chalcopyrite,  hematite,  cerussite,  anglesite, 
octahedral  fluor,  black  plilogopite  ;  elsewhere  in  KOSSIE,  calcite,  barite, 
quartz  crystals,  chondrodite  (near  Yellow  Lake], feldspar!  pargaxite! 
apatite;  pyroxene,  hornblende,  sphene,  zircon,  mica,  fluorite,  serpentine, 
automolite,  pearl  spar,  graphite. 

RUSSEL. — Pargusite,  hematite,  quartz  (dodeo.),  calcite,  serpentine, 
rensselaerite,  magnetite,  danburite!  with  pyroxene,  titanite,  biotite, 
hornblende. 

SARATOGA  CO. — GREENFIELD. —  Chrytoheryl !  garnet !  tourma- 
line !  mica,  feldspar,  apatite,  graphite,  aragonite  (in  iron  mines). 

SCHOHARIE  CO.— BALL'S  CAVE,  and  others.— Calcite,  stalac- 
tites. 

CARLISLE.- — Fibrous  barite,  cryst.  and  fibrous  calcite. 

SCHOHARIE. — Fibrous  celestite,  slrordianite !  cryxt.  pyrite! 

SULLIVAN  CO. — WURTZBORO'. — Galenite,  blende,  pyrite,  chalco- 
pyrite. 

ULSTER  CO. —  ELLENVILLE. —  Galenite,  blende,  chalcopyrite  ! 
quartz!  brookite. 

W A RR EN  CO. — CALDWELL. — Massive  feldxpar. 

CHESTER. — Pyrite,  tourmaline,  rutile,  chalcopyrite. 

DIAMOND  ISLE  (Lake  George). — Calcite,  quartz  crystals. 

JOHNSBURGH. — Fluorite!  zircon!  graphite,  serpentine,  pyrite. 

WASHINGTON  CO.— FORT  ANN.— Graphite,  serpentine. 

GRANVILLE. — Lamellar  pyroxene,  massive  feldspar,  epidote. 

WAYNE  CO.— WOLCOTT.— Barite. 

WESTCHESTER  CO.— ANTHONY'S  NOSE.— Apatite,  pyrite,  cal- 
cite! in  large  tabular  crystals,  grouped,  and  sometimes  incrusted 
with  drusy  quartz. 

CRUGER'S. — White  pyroxene,  hornblende,  magnetite  (with  green- 
ish spinel),  staurolite,  fibrolite. 

DAVENPORT'S  NECK. — Serpentine,  garnet,  sphene. 

EASTCHESTER. — Blende,  pyrite,  chalcopyrite,  dolomite. 

HASTINGS. — Tremolite,  white  pyroxene. 

NEW  ROCHELLE. — Serpentine,  quartz,  mica,  tremolite,  garnet, 
magnesite. 

PEEKSKILL. — Hornblende. 

RYE. — Serpentine,  chlorite,  black  tourmatine,  tremolite. 

SING  SING. — Pyroxene,  tremolite,  pyrite,  beryl,  azurite,  green 
malachite,  cerussite,  pyromophite,  anglesite,  vauquelinite,  galenite, 
native  silver,  chalcopyrite. 

WEST  FARMS. — Apatite,  tremolite,  garnet,  stilbite,  heulandite, 
chabazite,  epidote,  sphene. 


CATALOGUE   OF   AMERICAN   LOCALITIES   OF   MINERALS.    373 

YONKERS — Tremolite,  apatite,  calcite,  analcite,  pi/rite,  tourmaline. 
YORK/TOWN. — Fibrolite,  monazite,  magnetite. 
WYOMING  CO.— WYOMING.— Rock  salt. 


NEW  JERSEY. 

ANDOVER  IRON  MINE  (Sussex  Co.). — Willemite,  brown  garnet. 

ALLENTOWN  (Monmouth  Co.). —  V'ivianite,  dufrenite. 

BELLVILLE. — Copper  mines. 

BERGEN. — Calcite!  datolite!  pectolite!  analcite,  apophyllite!  gme- 
linite,  prehnite,  sphene,  stilbite,  natrolite,  heulandite,  laumontite,  cha- 
bazite,  pyrite,  pseudomorphous  steatite  imitative  of  apophyllite, 
diabantite. 

BRUNSWICK. — Native  copper,  malachite,  mountain  leather. 

BRYAM. — Chondrodite,  spinel,  at  Roseville,  epidote. 

CANTWELL'S  BRIDGE  (Newcastle  Co.)- — Vivianite. 

DANVILLE  (Jemmy  Jump  Ridge). — Graphite,  chondrodite,  augite. 

FLEMINGTON. — Copper  mines. 

FRANKFORT. — Serpentine. 

FRANKLIN  and  STERLING  (Sussex  Co.). — Spinel!  garnet!  rlwdon- 
ite!  willemite !  fran klinite!  zincite!  gahnite!  hornblende,  tremohte, 
chondrodite,  white  scapolite,  black  tourmaline,  epidote,  mica,  actinolite, 
augite,  sahlite,  coccolite,  asbestus,  jeffersonite  (augite),  calamine, 
graphite,  fluorite,  beryl,  galenite,  serpentine,  honey-colored  sphene, 
quartz,  chalcedony,  amethyst,  zircon,  molybdenite,  vivianite, 
tephroite,  rhodochrosite,  aragonite,  sussexite,  chalcophanite,  roepperite, 
calcozincite,  vanuxemite,  guhnite,  heiaerolite,  pyrochroite.  Also  al- 
gerite  in  gran,  limestone. 

FRANKLIN  and  WARWICK  MTS. — Pyrite. 

GRIGGSTOWN  and  GREENBROOK. — Copper-mines. 

HAMBURGH. — One  mile  north,  spinel!  tourmaline,  phlogopite,  horn- 
blende,  limonite,  hematite. 

HARRISONVILLE  (Gloucester  Co.). — Amber. 

HOBOKEN. — Serpentine  (marmolite),  brucite,  nemalite  (or  fibrous 
brucite),  aragonite,  dolomite. 

HURDSTOWN. — Apatite,  pyrrhotite,  magnetite. 

IMLAYSTOWN.  —Vivianite. 

LOCKWOOD. — Graphite,    chondrodite,    talc,    augite,    qvartz,    green 
spinel. 
'  MONTVILLE  (Morris  Co.). — Serpentine,  chrysotile. 

MULLICA  HILL  (Gloucester  Co.).—  Vimanite  lining  belemnites  and 
other  fossils. 

NEWTON. — Spinel,  blue,  pink,  and  white  corundum,  mica,  vesu- 
vianite,  Jwrnblende,  tourmaline,  scapolite,  rutile,  pyrite,  talc,  calcite, 
barite,  pseudomorphous  steatite. 

PATTERSON. — Datolite. 

ROSEVILLE  (Sussex  Co.). — Epidote. 

VERNON. — Serpentine,  spinel,  hydrotalcite. 

WEEHAWKEN. — Natrolite,  apophyllite. 


374  SUPPLEMENT  TO   DESCRIPTIONS   OF   SPECIES. 

PENNSYLVANIA.* 

ADAMS   CO. — GETTYSBURG. — Epidote,  fibrous  and  massive. 

BEDFORD  Co. — Bridgeport. — Barite. 

BERKS  CO.—  MORGANTOWN.— At  Jones's  mines,  1  m.  E.  of  Mor- 
gantown,  malachite,  native  copper,  chrysocolla,  magnetite,  allophane, 
pyrite,  chalcopyrite,  aurichalcite,  melacouite,  byssolite,  aragouite, 
apatite,  talc;  2  m.  N.  E.  from  Jones's  mine,  graphite,  spbeue;  at 
Steele's  mine,  magnetite,  micaceous  iron,  coccolite,  brown  garnet. 

READING. — Smoky  quartz  crystals,  zircon,  stilbite,  iron-ore;  near 
Pricetown,  zircon,  allanite,  epidote;  at  Eckbardt's  Furnace,  allanite 
with  zircon;  at  Zion's  Church,  molybdenite;  near  Kutztown,  in  the 
Crystal  Cave,  stalactites;  at  Fritz  Island,  apophyllite,  thomsonite,  cha- 
bazite,  calcite,  azurite,  malachite,  magnetite,  chalcopyrite,  stibuite, 
prochlorite,  precious  serpentine. 

BUCKS  CO. — BRIDGEWATER  STATION.  —  Titanite. 

BUCKINGHAM  TOWNSHIR — Crystallized  quartz;  near  New  Hope, 
vesuvianite,  epidote,  barite. 

SOUTHAMPTON. — Near  Feasterville,  in  G.  Vanarsdale's  quarry, 
graphite,  pyroxene,  sahlite,  coccolite,  sphene,  green  mica,  calcite, 
wollastomte,  glassy  feldspar  sometimes  opalescent,  phlogopite,  blue 
quartz,  garnet,  zircon,  pyrite,  moroxite,  scapolite. 

NEW  BRITAIN. — Dolomite,  galenite,  blende,  malachite. 

CARBON  CO. — SUMMIT  HILL,  in  coal-mines. — Kaolinite. 

CHESTER  CO.— AVONDALE.— Asbestus,  tremolite,  garnet!  opal, 
beryl  (yellow)! 

BIRMINGHAM  TOWNSHIP. — Amethyst,  serpentine. 

EAST  BRADFORD. — Near  Buffington's  bridge,  on  the  Brandywine, 
green,  blue,  and  gray  cyanite.  gray  crystals  loose  in  the  soil;  farms 
of  Dr.  Elwyn,  Mrs.  Foulke,  Win.  Gibbons,  and  Saml.  Entrikin,  ame- 
thyst ;  at  Strode's  mill,  aquacreptile,  oligoclase,  drusy  quartz,  colly- 
rite  f  on  Osborne's  Hill,  wad,  manganesian  garnet  (massive),  sphene; 
at  Caleb  Cope's  lime  quarry,  fetid  dolomite,  necrouite,  blue  cyanite, 
ialc ;  near  the  Black  Horse  Inn,  indurated  talc,  rutile;  on  Amos 
Davis's  farm,  ortJiite!  near  the  paper-mill  on  the  Brandywine,  zircon, 
menaccanite,  blue  quartz. 

WEST  BRADFORD. — Near  village  of  Marshalton,  green  cyanite;  at 
the  Chester  County  Poor-house  limestone  quarry,  chesterlite!  on 
dolomite,  rutile!  in  acicular  crystals,  damourite?  radiated  on  dolo- 
mite, quartz  crystals. 

CHARLESTOWN. — Pyromorphite,  cerussite,  galenite,  quartz,  ame- 
thyst. 

NORTH  COVENTRY. — Allanite,  near  Pughtown  black  garnets. 

EAST  GOSHEN. — Serpentine,  asbestus,  magnetite. 

ELK. — Menaccanite  with  muscovite,  chromite. 

WEST  GOSHEN.— On  the  Barrens,  1  m.  N.  of  West  Chester,  ser- 
pentine, indurated  talc,  deweylite,  radiated  magnetite,  aragonite, 
stauroltte,  asbestus;  zoisite  on  hornblende  at  West  Chester  water- 
works (not  accessible  at  present). 


*  See  also  the  Report  on  the  Mineralogy  of  Pennsylvania,  by  Dr.  F.  A.  Genth, 
1875. 


CATALOGUE   OF   AMERICAN   LOCALITIES   OF   MINERALS.    375 


GARDEN.  —  At  Nivin's  limestone  quarry,  'brown  and  yellow 
tourmaline,  necronite,  aragonite,  fibrolite,  kaolinite,  tremolite. 

KENNETT.  —  Actinolite,  tremolite;  on  Wm.  Cloud's  farm,  sumtone! 
at  Pearce's  old  mill,  sumtone. 

EAST  MARLBORO  UGH.  —  On  farm  of  Bailey  &  Brother,  1  m.  S.  of 
Uuionville,  yellow  and  white  tourmaline,  chesterlite  ;  near  Marl  bor- 
ough meeting-house,  serpentine,  zircon  loose  in  the  soil  at  Pusey's 
sawmill. 

WEST  MABLBOROUGH.  —  Near  Logan's  quarry,  cyanite,  yellow 
tourmaline,  rutile;  near  Doe  Run  village,  tremolite:  in  R.  Baily's 
limestone  quany,  2^  m.  S.  W.  of  Uuionville,  fibrous  tremolite,  cy- 
anite. 

NEWLIN.  —  \\  m.  N.  E.  of  Unionville,  corundum!  often  in  loose 
crystals  with  a  coating  of  steatite,  diaspore!,  spinel  (black),  picro- 
lile,  black  tourmaline  with  flat  pyramidal  terminations  in  albite, 
euphyllite,  feldspar,  beryl!  in  one  crystal  weighing  51  Ibs.,  pyrite, 
chloritoid,  diallage,  oliyoclase;  menaccanite,  dinochlore,  albite,  ortho- 
clane,  halloj'site,  margarite,  garnets,  beryl;  on  J.  Lesley's  farm, 
corundum,  a  single  mass  weighing  over  100  tons,  diaspore!  ;  in  Ed- 
wards's  limestone  quarry,  rutile;  C.  Passmore's  farm,  amethyst. 

EAST  NOTTINGHAM.  —  Asbestus,  chromite  in  crystals,  hallite. 

WEST  NOTTINGHAM.  —  At  Scott's  chrome-mine,  chromite.  foliated 
talc,  marmolite,  serpentine,  rhoclochrome  ;  near  Moro  Phillips's 
chrome-mine,  asbestus  ;  at  the  magnesia  quany,  deweylUe,  marmo- 
lite, magnesite,  leelite,  serpentine,  chromite,  meerschaum;  Lear  Fre- 
mont P.'O.,  corundum. 

WEST  PIKELAND.  —  In  iron-mines  near  Chester  Springs,  turgite, 
hematite  (stalactitical  and  in  geodes),  gothite. 

PENNSBURY.—  On  John  Craig's  farm,  brown  garnets,  mica;  on  J. 
Dilworth's.  near  Fairville,  muscomte!  in  Fairville,  sunstone  ;  near 
Brin  ton's  Ford,  chondrodite,  sphene,  augite  ;  at  Swain's  quarry,  or- 
thoclasc,  muscovite  containing  magnetite. 

POCOPSON.  —  Farms  of  J.  Entrikiu  and  J.  B.  Darlington,  amethyst, 

SADSBURY.  —  Rutile!  crystals  loose  for  7  m.  along  the  valley,  near 
the  village  of  Parkesburg;  near  Sadsbury  village,  amethyst. 

SCHUYLKILL.  —  In  railroad  tunnel  at  PHOSNIXVILLE,  dolomite!, 
quartz  crystals,  calcite  ;  at  the  WHEATLEY,  BEOOKDALE,  and  CHES- 
TER COUNTY  LEAD-MINES  (now  abandoned,  and  good  specimens 
not  obtainable).  1|  m.  S.  of  Phocnixville,  pyromorphite  !  cerussite! 
galenite,  anglesite!  quartz  crystals,  chalcopyrite,  barite,  fluorite 
(white),  stolzite,  wulfenite!  calamine,  vanadinite,  blende!  mimetite! 
descloizite,  gothite,  chrysocolla,  native  copper,  malachite,  azurite, 
limonite,  calcite,  sulphur,  pyrite,  melaconite,  pseudomalachite,  gers- 
dorffite,  chalcocite  ?  covellite. 

WILLISTOWN.  —  Magnetite,  chromite. 

WEST  TOWN.—  On  the  serpentine  rocks,  3  m.  S.  of  West  Chester, 
dinochlore!  jefferisite  !  actinolite. 

WEST  WHITELAND.  —  At  Gen.  Trimble's  iron-mine  (southeast), 
stalactitic  hematite!  wavellite!  !  in  radiated  stalactites,  gibbsite. 

WARWICK.  —  Elizabeth  mine  and  Keim's  mine  1  m.  N.  of  Knauer- 
town,  aplome  garnet!  micaceous  hematite,  pyrite  (octahedral),  chal- 
copyrite massive  and  in  crystals,  magnetite,  brown  garnet,  calcite, 


376  SUPPLEMENT  TO   DESCRIPTIONS   OF   SPECIES. 

by&solite!  serpentine;  near  village  of  St.  Mary's,  magnetite  (clode- 
cahedral),  melanite,  garnet,  actinolite  ;  at  Hope  well  iron-mine,  1  m. 
N.  W.  of  St.  Mary's,  magnetite  in  octahedral  crystals. 

YELLOW  SPRINGS. — Allanite. 

DAUPHIN  CO. — NEAR  HUMMERSTOWN. — Green  garnets,  cryst. 
smoky  quartz,  feldspar. 

DELAWARE  CO. —  ASTON  TOWNSHIP.  —  AmetJiyst,  corundum 
(Village  Green),  fbrolite,  black  tourmaline,  margarite,  sunstone,  asbes- 
tus, anthopyllite,  steatite;  Bridgewater  Station,  Titanite,  in  twins 
and  translucent;  at  Peter's  mill-dam  in  the  creek,  pyrope  garnet. 

BIRMINGHAM. — Flbrolite,  kaolin  (abundant),  rutile,  amethyxt ;  at 
Bullock's  old  quarry,  zircon,  bucholzite. 

CHESTER. — Amethyst,  black  tourmaline,  beryl,  crystals  of  orthoclase, 
beryl,  garnet,  molybdenite,  molybdite,  uraninite,  muscovite. 

CHICHESTER. — Near  Trainer's  mill-dam,  beryl,  tourmaline,  feldspar. 

CONCORD. — Mica,  feldspar,  kaolin,  drusy  quartz,  garnet,  antho- 
pliyllite,  fihrolite,  amethyst,  manganesian  garnet,  meerschaum;  in 
Green's  creek,  pyrope  garnet. 

DARBY. — Blue  and  gray  cyanite,  beryl,  garnet,  smoky  quartz. 

EDGEMONT. — Amethyst;  1  m.  E.  of  Edgemoiit  Hall,  rutile  in 
quart  z. 

LEIPERVILLE.— Garnet,  zoisite,  heulandite,  leidyite,  beryl  (De- 
shong's  qu  ),  black  tourmaline. 

MARPLE. — Tourmaline,  andalusite,  amethyst,  actinolite,  bronzite, 
talc,  radiated  actinolite  in  talc,  chromite,  beryl,  menaccanite  in  quartz, 
amethyst. 

MIDDLETOWN. — Amethyst,  beryl,  black  mica,  mica  dendritic  with 
magnetite,  manganesian  garnets!  some  3  inches  in  diameter,  indurated 
talc,  rutile,  mica,  green  quartz!  anthophyllite,  radiated  tourmaline,  stau- 
rolite,  titanic  iron,  fibrolite,  serpentine;  at  Lenni,  chlorite,  green  and 
bronze  vermiculite  !  green  feldspar ;  at  Mineral  Hill,  crystals  of  corun- 
dum, some  of  6  inches,  actinolite,  bronzite,  green  feldspar,  moonstone, 
sunstone,  magnesite,  chromite  (octahedrons),  columbite,  beryl,  asbestus, 
rutile,  melanosiderite,hallite;  at  Painter's  Farm,  zircon  with  oligoclase, 
trcmolite,  tourmaline;  at  Hibbard's  Farm  and  at  Fairlamb's  Hill,  chro- 
mite  in  brilliant  octahedrons;  John  Smith  farm,  meerschaum. 

NEWTOWN. — Serpentine,  hematite,  enstatite. 

UPPER  PROVIDENCE. — Anthophyllite,  radiated  asbestus,  andalusite, 
radiated  actinolite,  tourmaline,  beryl,  green  feldspar,  amethyst,  (one  of  7 
Ibs.  from  Morgan  Hunter's  farm),  andalusite! ;  at  Blue  Hill,  blue 
quartz  in  chlorite,  amianthus  in  serpentine. 

LOWER  PROVIDENCE. — Amethyst,  garnet,  feldspar  !  (large  crystals). 

RADNOR.  —  Garnet,  mannolite,  deweylite,  chromite,  asbestus,  mag- 
nesite, picrolite,  bronzite. 

SPRINGFIELD. — Andalusite,  tourmaline,  beryl,  titanic  iron,  garnet; 
on  Fell's  Laurel  Hill,  beryl,  garnet;  near  Lewis's  paper-mill,  allophane, 
mica,  albite. 

WATERVILLE. — Near  Chester  and  Upland,  chabazite. 

FRANKLIN  CO.— LANCASTER  STATION.— Barite. 

HUNTINGDON  CO.— Near  FRANKSTOWN.— In  a  bed  of  a  stream 
and  on  a  hill-side,  fibrous  celestite,  quartz  crystals. 

LANCASTER  CO.— DRUMORE  TOWNSHIP.— Quartz  crystals. 


CATALOGUE   OF   AMERICAN   LOCALITIES   OF   MINERALS.    377 

FULTON. — At  Wood's  chrome  mine,  near  Texas,  brucite  !  zaratite 
(emerald  nickel),  pennite!  ripidolite!  Mmmererite!  enstattte,,  bromite, 
baltimorUe,  chromite,  williamsite,  chrysolite!  marmolite,  picrolite,  hy- 
dromagnesite,  dolomite,  magnesite,  aragonite,  calcite,  serpentine,  hem- 
atite, menaccanite,  genthite,  chrome-garnet,  bronzite,  millerite;  at 
Low's  mine,  hydromagnesite,  brucite  (lancasterite),  picrolite,  magnesite, 
williamsite,  chromic  iron,  talc,  zaratite,  baltimorite,  serpentine^  hema- 
tite; on  M.  Boice's  farm,  1  m.  N.  W.  of  village,  pyrite,  enstatite;  near 
Rock  Springs,  chalcedony,  carnelian,  moss  agate,  green  tourmaline  in 
talc,  titanic  iron,  chromite,  octahedral  magnetite  in  chlorite;  at  Rey- 
nolds's  old  mine,  calcite,  talc,  picrolite,  chromite;  at  Carter's  chrome 
mine,  brookite. 

GAP  MINES.— Chalcopyrite,  pyrrhotite  (niccoliferous),  millerite 
(botryoidal  radiations),  mmanite !  actinolite,  siderite,  hisingerite, 
pyrite. 

PEQTJEA  VALLEY. — 8  m.  S.  of  Lancaster,  argentiferous  galenite, 
vauquelinite,  rutile  at  Pequea  mine;  4  m.  N.  W.  of  Lancaster,  cata- 
mite, galenite,  blende ;  pyrite  in  cubes  near  Lancaster;  at  the  Lancaster 
zinc  mines,  calamine,  blende,  tennantite?  smithsonite  (pseud,  of  dolo- 
mite), aurichalciie. 

LEBANON  CO.— CORNWALL. — Magnetite,  pyrite  (cobaltiferous), 
chalcopyrite,  native  copper,  azurite,  malachite,  chrysocolla,  cuprite  (hy- 
drocuprite),  allophane,  brochantite,  serpentine,  quartz  pseudpmorphs; 
galenite  (with  octahedral  cleavage),  fluorite,  covellite,  hematite  (micar 
ceous),  opal,  asbestus. 

LEHIGH  CO.—  FRIEDENSVTLLE. — At  zinc  mines,  calamint,  smith- 
sonite,  hydrozincite,  massive  blende,  greenockite,  quartz,  allophane, 
mountain  leather,  aragonite,  sauconite;  near  Allentown,  magnetite, 
pipe-iron  ore;  near  Bethlehem,  on  S.  Mountain,  allanite,  with  zircon, 
magnetite,  martite,  black  spinel,  tourmaline,  chalcocite. 

SHIMEKVILLE  . — Corundum . 

LUZERNE  CO.— SORANTON.— Under  peat,  phytocollite. 

DRIFTON.— Pyrophyilite.  » 

MIFFLIN  CO.— Strontianite. 

MONROE  CO. — In  CHERRY  VALLEY,  calcite,  chalcedony,  quartz; 
in  Poconac  Valley,  near  Judge  Mervine's,  cryst.  quartz. 

MONTGOMERY  CO.— CONSHOHOCKEN.— Fibrous  tourmaline,  me- 
naccanite, aventurine  quartz,  phyllite;  in  the  quarry  of  Geo.  Bullock, 
calcite  in  hexagonal  prisms,  aragonite. 

LOWER  PROVIDENCE. — Perkiomen  lead  and  copper  mines,  near 
village  of  Shannonville,  azurite,  blende,  galenite,  pyromorphite,  cerus- 
site,  wulfenite,  anglesite,  barite,  calamine,  chalcopyrite,  malachite, 
chrysocolla,  brown  spar,  cuprite,  covellite  (rare),  melaconite,  libethen- 
ite,  pseudomalachite. 

WHITE  MARSH. — If.  O.  Hitner's  iron  mine,  limonite  in  geodes  and 
stalactites,  gothite,  pyrolusite,  wad,  lepidocrocite;  at  Edge  Hill  Street, 
North  Pennsylvania  Railroad,  titanic  iron,  braunite,  pyrolusite;  1  m. 
S.  W.  of  Hitner's  iron  mine,  limonite,  turgite,  gothite,  pyrolusite,  velvet 
manganese,  wad;  near  Marble  Hall,  at  Hitner's  marble  quarry,  white 
marble,  granular  barite,  resembling  marble;  at  Spring  Mills,  limonite, 
pyrolusite,  gOthite;  at  Flat  Rock  Tunnel,  opposite  Mauayunk,  stilbite, 
heulandite,  chabasite,  ilvaite,  beryl,  feldspar,  mica. 


378  SUPPLEMENT  TO   DESCRIPTION'S  OF  SPECIES. 

LAFAYETTE,  at  the  Soapstone  quarries. — Talc,  jefferisite,  garnet, 
albite,  serpentine,  zoisite,  staurolite,  chalcopyrite;  at  Rose's  Serpentine 
quarry,  opposite  Lafayette,  enstatite,  serpentine. 

NORTHAMPTON  CO.— BETHLEHEM.— Axinite,  zircon  (f  m.  N.). 

BUSHKILL  T. — Crystal  Spring  on  Blue  Mountain,  quartz  crystals. 

NAZARETH. — Quartz  crystals. 

Near  EASTON.— Zircon!  (exhausted),  nephrite,  coccolite,  tremolite, 
pyroxene,  sahlite,  limonite,  magnetite,  purple  calcite,  bowenite. 

WILLIAMS  TOWNSHIP. — Pyrolusite  in  geodes  in  limoiiite  beds, 
gothite  (lepidocrocite)  at  Glendon. 

NORTHUMBERLAND  CO.— Opposite  SELIN'S  GROVE.— Cala- 
mine. 

PHILADELPHIA  CO.— FRANKFORD.— Titanite  in  gneiss,  apo- 
phyllite;  at  the  quarries  on  Frankford  Creek,  stilbite,  molybdenite, 
hornblende;  on  the  Connecting  Railroad,  wad,  earthy  cobalt;  at  Chest- 
nut Hill,  magnetite,  green  mica,  chalcopyrite,  fluorite. 

FAIRMOUNT  WATER- WORKS  —In  quarries  opposite  Fairmount, 
autunite  !  torbernite,  orthoclase,  beryl,  tourmaline,  albite,  wad,  menac- 
canitc. 

GORGAS'S  and  CREASE'S  LANE. — Tourmaline,  cyanite,  staurolite, 
hornstonc,  fahlunite. 

Near  GERMANTOWN.—  Black  tourmaline,  laumontite,  apatite;  York 
Road,  tourmaline,  beryl. 

HEFT'S  MILL.— Alunogen,  tourmaline,  cyanite,  titanite. 

MANAYUNK. — At  the  soapstone  quarries  above  Manayunk,  talc, 
steatite,  chlorite,  vermiculite,  anthophyliite,  staurolite,  dolomite,  apa- 
tite, asbestus,  brown  spar,  epsomite. 

MEAGARGEE'S  Paper  mill. — Staurolite,  titanic  iron,  hyalite,  apatite, 
green  mica,  iron  garnets  in  abundance. 

McKiNNEY's  QUARRY,  on  Rittenhouse  Lane. — Feldspar,  apatite, 
stilbite,  natrolite,  heulandite,  epidote,  hornblende,  bornite,  malachite. 

SCHUYLKILL  FALLS. — Chabazite,  titanite,  fluorite,  epidote,  musco- 
Vite,  tourmaline,  prochlorite. 

SCHUYLKILL  CO.—  TAMAQUA,  near  POTTSYILLE,  in  coal-mines. 
— Kaolinite. 

Near  MAHANOY  CITY. — Pyrophyllite,  alunogen,  copiapite,  in  coal- 
mines. 

YORK  CO. — Bornite,  rutile  in  slender  prisms  in  granular  quartz. 

DELAWARE. 

NEWCASTLE  CO.— BRANDYWINE  SPRINGS. — Fibrolite  abundant, 
sahlite,  pyroxene;  Brandy  wine  Hundred,  muscovite,  enclosing  reticu- 
iated  magnetite,  garnet. 

DIXON'S  FELDSPAR  QUARRIES,  6  m.  N.  W.  of  Wilmington  (not 
open). — Beryl,  apatite,  cinnamon-stone!  magnesite,  serpentine,  asbes- 
tus, black  tourmaline!  cyanite. 

EASTBURN'S  LIMESTONE  QUARRIES,  near  the  Pennsylvania  line. — 
Tremolite,  bronzite. 

QUARRYVILLE. — Garnet,  fibrolite. 

Near  NEWARK,  on  the  railroad. — Spba3rosiderite  on  drusy  quartz, 
jasper  (ferruginous  opal),  cryst.  siderite  in  cavities  of  cellular  quartz, 
quartz  crystals  loose  in  soil. 


CATALOGUE   OF  AMERICAN   LOCALITIES   OF  MINERALS.    379 

WAY'S  QUARRY,  2  m.   S.  of  Centreville. — Feldspar  in  cleavage 
masses,  apatite,  mica,  deweylite,  granular  quartz. 
WILMINGTON. — In  Christiana  quarries,  hypcrsthene. 
KENNETT  TURNPIKE,  near  Centreville. — Cyanite  and  garnet. 
KENT  CO. — Near  MIDDLETOWN,  Folk's  marl -pits,  mmanite! 
SUSSEX  CO.— Near  CAPE  HENLOPEN.— Vivianite. 

MARYLAND. 

BALTIMORE  (Jones's  Falls,  If  mile  from  B.).— Chabazite  (hayden- 
ite),  heulandite  (beaumontite),  pyrite,  siderite,  mica,  stilbite. 

16  in.  from  Baltimore,  on  the  Gunpowder,  graphite ;  23  m.  from 
B.,  on  the  Gunpowder,  talc;  25  m.  from  B.,  on  the  Gunpowder, 
magnetite,  sphene,  pycnite ;  8  to  20  m.  N.  of  B.,  in  limestone,  tremo- 
liie,  augite,  pyrite,  brown  and  yellow  tourmaline  ;  15  m.  N.  of  B., 
sky-blue  cJialcedony  in  granular  limestone;  18  m.  N.  of  B.,  at  Scott's 
mills,  magnetite,  cyanite. 

BARE  HILLS. — Chromite,  asbestus,  tremolite,  talc,  hornblende,  ser- 
pentine, chalcedony,  meerschaum,  baltiinorite,  chalcopyrite,  magnetite, 
enstatite,  bronzite. 

CAPE  SABLE,  near  Magothy  R. — Amber,  pyrite,  alum  slate. 

CARROLL  Co. — Near  Sykesville,  Liberty  Mines,  gold,  magnetite, 
pyrite  (octahedrons),  cJialcopyrite,  linnseite  (carrollite) ;  at  Patapsco 
Mines,  near  Finksburg,  bornite,  malachite,  siegenite,  linnceite,  reming- 
tonite,  magnetite,  chalcopyrite ;  at  Mineral  Hill  mine,  bornite,  chalco- 
pyrite, linnseite,  gold,  magnetite. 

CECIL  Co.,  north  part. — Chromite  in  serpentine. 

COOPTOWN,  Hartford  Co. — Olive-colored  tourmaline,  diaUage,  tile 
of  green,  blue,  and  rose  colors,  ligniform  asbestus,  ch^omile,  serpentine. 

DEER  CREEK. — Magnetite!  in  chlorite  slate. 

FREDERICK  Co. — Old  Liberty  mine,  near  Liberty  Town,  black  cop- 
per, malachite,  chalcocite,  hematite;  at  Dollyhyde  mine,  bornite,  chal- 
copyrite, pyrite,  argentiferous  gjilenite  in  dolomite. 

MONTGOMERY  Co. — Oxide  of  manganese. 

SOMERSET  and  WORCESTER  Cos.,  N.  part.— Bog-ore,  mvianite. 

ST.  MARY'S  RIVER.— Qypsum!  in  clay. 

PYLESVILLE,  Hartford  Co. — Asbestus  mine. 

VIRGINIA,  WEST  VIRGINIA,  AND  DISTRICT  OF 
COLUMBIA. 

ALHEMARLE  Co. ,  a  little  west  of  the  Green  Mts.— Steatite,  graphite, 
galenite. 

AMELIA  Co. — Near  Court  House,  mica!  orthoclase,  microlite! 
columbite,  oi*thite,  helvite,  topazolite,  amethyst,  fluorite,  apatite. 

AMHERST  Co. — Along  the  west  base  of  Buffalo  Ridge,  copper  ores; 
on  N.  W.  slope  of  Friar  Mtn.,  allanite,  magnetite,  zircon. 

AUGUSTA  Co. — At  Weyer's  (or  Weir's)  cave,  calcite,  stalactites. 

BUCKINGHAM  Co.— Gold  at  Garnctt  and  Moseley  mines,  also,  pyrite, 
pyrrhotite,  calcite,  garnet;  at  Eldridge  mine  (now  London  and  Vir- 
ginia mines)  near  by,  and  the  Buckingham  mines  near  Maysvillc,  gold, 
auriferous  pyrite,  chalcopyrite,  tennautite,  barite;  cyanite,  tourmalinet 
actinolite. 


380  SUPPLEMENT  TO   DESCRIPTIONS   OF   SPECIES. 

CHESTERFIELD  Co. — Near  this  and  KichmondCo.,  bituminous  coal, 
native  coke.  At  Manchester,  diamond. 

CULPEPPER  Co.,  on  Rapidan  River. — Gold,  pyrite. 

FRANKLIN  Co.— Grayish  steatite. 

FAUQUIER  Co.,  Barnett's  mills. — Asbestus,  gold  mines,  barite,  cal- 
cite. 

FLUVANNA  Co. — Gold  at  Stockton's  mine;  also  tetradymite,  at 
"  Tellurium  mine." 

PHENIX  COPPER  MINES.— Chalcopyrite,  etc. 

GOOCHLAND  Co. — Gold  mines  (Moss  and  Busby's). 

HARPER'S  FERRY,  on  both  sides  of  the  Potomac. — Thuringite 
(owenite)  with  quartz. 

JEFFERSON  Co.,  at  Shepherdstown. — Fluor. 

KANAWHA  Co. — At  Kanawha,  petroleum,  brine  springs,  cannel  coal. 

LOUDON  Co. — Tabular  quartz,  prase,  'pyrite,  talc,  chlorite,  soapstone, 
asbestus,  chromite,  actinolite,  quartz  crystals  ;  micaceous  iron,  bornite, 
malachite,  epidote,  near  Leesburg  (Potomac  mine). 

LOUISA  Co. — Walton  gold  mine,  gold,  pyrite,  chalcopyrite,  argen- 
tiferous galenite,  siderite,  blende,  anglesite;  boulangerite,  blende  (at 
Tinder's  mine);  corundum  (40  m.  N.  of  Richmond). 

NELSON  Co. — Galenite,  chalcopyrite,  malachite. 

ORANGE  Co.— Western  part,  Blue  Ridge,  hematite ;  gold  at  the 
Orange  Grove  and  Vaucluse  gold  mines,  worked  by  the  "Freehold" 
and  "Liberty"  Mining  Companies. 

ROCKBRIDGE  Co.— 3  m.  S.  W.  of  Lexington. — Barite,  dufrenite,  in 
bed  10  in.  thick,  with  strengite. 

SHENANDOAH  Co.,  near  Woodstock. — Fluorite. 

SPOTTSYLVANIA  Co.,  2  m.  N.  E.  of  Chancellorsville.— Cyanite  ; 
gold  mines  at  the  junction  of  the  Rappahannock  and  Rapidan ;  on 
the  Rappahannock  (Marshall  mine);  Whitehall  mine,  affording  also 
tetradymite. 

STAFFORD  Co  ,  8  or  10  m.  from  Falmouth. — Micaceous  iron,  gold, 
tetradymite,  silver,  galenite,  vivianite. 

WASHINGTON  Co. — 18  m.  from  Abingdon. — Halite,  gypsum. 

WYTHE  Co.  (Austin's  mines).  —Cerussife,  minium,  plumbic  ochre, 
blende,  calamine,  galenite,  graphite,  aragonite. 

On  the  Potomac,  25  m.  35?.  of  Washington. — Sulphur  in  limestone. 

NORTH  CAROLINA. 

ALEXANDER  Co.  —At  Stony  Point,  spodumene  var.  hiddenite  !  beryl ! 
emerald!  rutile  (in  quartz),  monazite,  allanite,  quartz,  smoky  quartz. 
At  White  Plains,  quartz  crystals,  hiddenite,  beryl,  rutile,  columbite, 
tourmaline,  scorodite.  At  Milholland's  mill,  rutile,  monazite,  musco- 
mte,  quartz. 

BUNCOMBE  Co.— In  the  mica  mines,  muscovite  !  orthoclase!  garnet; 
at  Swannanda  Gap,  corundum  in  cyanite. 

BURKE  Co.— Gold,  monazite,  zircon,  beryl,  corundum,  garnet, 
sphene,  smoky  quartz,  graphite,  iron  ores,  tetradymite,  montanite;  in 
gravels  at  Brindletown,  octahedrite,  brookite,  zircon,  fergusonite,  mona- 
zite, xenotime  (twinned  with  zircon),  samarskite  garnet,  tourmaline, 
magnetite;  Lmville  Mtn.,  itacolumyte. 


CATALOGUE   OF   AMERICAN   LOCALITIES  OF  MINERALS.    SL 

CABARRTJS  Co. — Phenix  Mine,  gold,  barite,  chalcopyrite,  auriferous 
^covellite,  pyrite,  quartz  pscudomorph  after  barite,  tetradymite,  mon- 
"tanite;  Pioneer  mines,  gold,  limonite,  pyrolusite,  barnhardtite,  wolfram, 
scheelite,  cuprotungstite,  tungstite,  diamond,  chrysocolla,  chalcocite, 
molybdenite,  chalcopyrite,  pyrite ;  White  mine,  needle  ore,  chalcopy- 
rite, barite;  Long  and  Muse's  mine,  argentiferous  galenite,  pyrite, 
chalcopyrite,  limonite;  Boger  mine,  tetradymite;  Fink  mine,  valuable 
copper  ores ;  McMakin's,  tetrahedrite,  argentite,  barite,  magnetite, 
talc,  blende,  pyrite,  proustite,  galenite,  pyrolusite;  Bangle  mine, 
scheelite. 

CALDWELL  Co.— Chromite,  beryl,  garnet;  near  Patterson,  serpen- 
tine. 

CATAWBA  Co. — Garnet,  smoky  quartz. 

CHATHAM:  Co. — Mineral  coal,  pyrite,  chloritoid,  bornite,  chalcopy- 
rite, rutile  in  quartz,  muscomte,  pyrophyllite  (slaty). 

CHEROKEE  Co. — Near  Valley  River,  tremolite,  ialc  (white  steatite), 
marble  of  various  colors,  limonite  ;  staurolite  (Parker  mine). 

CLEVELAND  Co. — White  Plains,  quartz  crystals,  smoky  quartz,  tour- 
maline, rutile  in  quartz. 

CLAY  Co. — At  the  Cullakenee  mine  and  elsewhere,  corundum  (pink), 
zoisite,  tourmaline,  margarite,  willcoxite,  dudleyite,  picrolite;  Tus- 
quitee  Cr.,  staurolite;  at  Shooting  Creek,  chrysolite. 

DAVIDSON  Co. — King's,  now  Washington  mine,  native  silver,  cerus- 
site,  anglesite,  scheelite,  pyromorphite,  galenite,  blende,  malachite, 
black  copper,  icavellite,  garnet,  stilbite;  5  m.  from  Washington  mine, 
on  Faust's  farm,  gold,  tetradymite,  oxide  of  bismuth  and  tellurium, 
montanite,  chalcopyrite,  limonite,  siderite,  epidote ;  near  Squire 
Ward's,  gold  in  crystals,  electrum. 

FRANKLIN  Co. — At  Partiss  mine,  diamond. 

GASTON  Co. — Iron  ores,  corundum,  margarite;  near  Crowder's 
Mountain  (in  what  was  formerly  Lincoln  Co.),  lazulite,  cyanite,  garnet, 
corundum,  rutile,  margarite,  graphite;  also  20  in.  N.  E.,  near  S.  end 
of  Clubb's  Mountain,  lazulite,  cyanite,  talc,  rutile,  topaz,  pyrophyllite, 
corundum;  King's  Mountain  (or  Briggs)  mine,  native  tellurium, 
altaite,  nagyagitc,  tetradymite,  montanite,  corundum,  sphalerite. 

GCILFORD  Co. — McCulloch  copper  and  gold  mine,  12  m.  from 
Greensboro',  gold,  pyrite,  chalcopyrite  (worked  for  copper),  quartz,  sid- 
erite; at  Deep  River,  compact  pyrophyllite  (worked  for  slate-pencils); 
at  Gibsonville,  green  quartz. 

HAYWOOD  Co. — Corundum,  margarite,  damourite ;  Caster  mine, 
corundum. 

HENDERSON  Co. — Zircon,  sphcne  (xanthitane). 

IREDELL  Co. — States  ville,  corundum  enveloped  in  margarite,  quartz 
crystals,  cyanite,  actinolite. 

JACKSON  Co.— Alunogen?  at  Smoky  Mountain;  at  Webster,  serpen- 
tine, chromite,  genthite,  enstatite,  chrysolite,  talc;  Hogback  Mountain, 
pink  corundum,  margarite,  tourmaline. 

LINCOLN  Co. — Diamond;  at  Randleman's,  amethyst,  rose  quartz, 
graphite. 

MACON  Co. — Near  Franklin,  Culsagee  and  other  mines;  corundum! 
spinel,  diaspore,  chromite,  chrysolite,  talc,  enstatite,  tremolite,  tour- 
maline, damourite,  prochlorite,  culsageeite,  kerrite,  maconite;  Jenk's 


382          SUPPLEMENT  TO   DESCRIPTIONS   OF   SPECIES. 

mine,  corundum! ;  Thorn  Mtn.,  beryl;  in  the  mica  mines,  biotite  in 
muscovite. 

McDowELL  Co. — Brookite,  monazite,  corundum  in  small  red  and 
white  crystals,  pyrophyllite,  zircons,  garnet,  beryl,  sphene,  xenotime, 
rutile,  iron  ores,  pyromelane,  tctradymite,  montanite. 

MADISON  Co. — 20  m.  from  Asheville,  corundum,  margarite,  chlorite; 
Carter's  mine,  beryl;  staurolite. 

MECKLENBURG  Co. — Near  Charlotte  (Rhea  and  Cathay  mines)  and 
elsewhere,  chalcopyrite,  gold,  zircon;  chalcptrichite  at  McGinn's  mine; 
barnhardtite  near  Charlotte;  pyrophyllite  in  Cotton  Stone  Mountain, 
diamond;  Flowe  mine,  scheelite,  wolframite;  Todd's  Branch,  mona- 
zite, diamond. 

MITCHELL  Co. — At  the  Wiseman  mica  mine,  muscomte  !  samars- 
Aite  f  hatchettolite,  euxenite,  columbite,  rogersite,  uraninite,  uranotile, 
allanite,  beryl,  zoisite,  garnet,  menaccanite,  gummite,  uraconite,  fer- 
gusonite,  torbernite,  autunite;  at  Grassy  Creek  mine,  muscomte,  beryl, 
samarskite;  at  Deake  mine,  gahnite,  mica,  monazite!  uraninite, 
uranotile,  gummite,  uranochre;  near  Bakersville,  chrysolite. 

MONTGOMERY  Co. — Steele's  mine,  Cotton  Stone  Mtn.,  ripidolite, 
albite,  pyrophyllite. 

MOORE  Co. — Carbonton,  compact  pyrophyllite  (large  beds  on  Lin- 
ville  Mtn.). 

ORANGE  Co. — At  Hillsboro',  pyrophyllite. 

RANDOLPH  Co. — At  Pilot  Knob,  pyrophyllite. 

ROWAN  Co.— Gold  Hill  mines,  38  m.  N.  E.  of  Charlotte,  and  14  m. 
from  Salisbury,  gold,  auriferous  pyrite;  10  m.  from  Salisbury,  feldspar 
in  crystals,  bismuthinite. 

RUTHERFORD  Co. — Gold,  graphite,  bismuthic  gold,  diamond,  eu- 
clase,  pseudomorphous  quartz  f  chalcedony,  corundum  in  small 
crystals,  epidote,  pyrope,  brookite,  zircon,  monazite,  rutherfordite, 
samarskite,  quartz  crystals,  itacolumyte;  on  the  road  to  Cooper's  Gap, 
cyanite. 

UNION  Co. — Lemmond  gold  mine,  18  m.  from  Concord  (at  Stewart's 
and  Moore's  mine),  gold,  blende,  argentiferous  galenite,  pyrite,  chal- 
copyrite. 

WAKE  Co. — Graphite. 

WATAUGA  Co.— At  Rich  Mtn.,  chrysolite,  chromite. 

YANCEY  Co. — Iron  ores,  amianthus,  chromite,  chrysolite,  garnet 
(spessartite),  cyanite,  samarskite,  columbite,  corundum,  spinel;  at  Ray 
mica  mine,  muscomte,  tantalite  (columbite),  monazite,  beryl,  garnet, 
zircon,  rutile ;  at  Hampton's,  chromite,  epidote,  enstatite,  tremolite, 
chrysolite,  serpentine,  talc, 


SOUTH  CAROLINA. 

ABBEVILLE  Co. — Oakland  Grove,  gold  (Dorn  mine),  galenite,  pyro- 
morphite,  amethyst,  garnet. 

ANDERSON  Co. — At  Pendleton,  actinolite,  galeuite,  kaolin,  tourma- 
line, zircon. 

CHEOWEE  VALLEY. — Galenite,  tourmaline,  gold. 

CHESTERFIELD  Co. — Gold  (Brewer's  mine),  talc,  chlorite,  pyrophyl- 
lite, pyrite,  native  bismuth,  bismuth  carbonate,  red  and  yellow  ochre, 
whetstone,  enargite. 


CATALOGUE   OF   AMERICAN    LOCALITIES   OF   MINERALS.    383 

GREENVILLE  Co. — Galenite,  pyromorphite,  kaolin,  chalcedony  in 
buhl-stone,  beryl,  plumbago,  epidote,  tourmaline. 

KERSHAW  Co.— Buttle. 

LANCASTER  Co. — Gold  (Hale's  mine),  talc,  chlorite,  cyanite,  ita- 
columyte,  pyrite ;  gold  also  at  Blackman's  mine,  Massey's  mine, 
Ezell's  mine. 

LAUBENS  Co. — Corundum,  damourite. 

NEWBERRY  Co. — Leadhillite. 

PICKENS  Co.— Gold,  manganese  ores,  kaolin. 

HIGHLAND  Co.— Chiastolite,  novaculite. 

SPARTANBURG  Co.— Magnetite,  chalcedony,  hematite  ;  at  the  Cow- 
pens,  limonite,  graphite,  limestone,  copperas ;  Morgan  mine,  leadhill- 
ite,  pyromorphite,  cerussite. 

UNION  Co. — Fairforest  gold-mines,  pyrite,  chalcopyrite. 

YORK  Co. — Whetstone,  witherite,  barite,  tetradymite. 

GEORGIA. 

BURKE  AND  SCRTVEN  Cos. — Hyalite. 

CHEROKEE  Co. — At  Canton  Mine,  chalcopyrite,  galenite,  claustha- 
lite,  plumbogummite,  hitchcockite,  arsenopyrite,  lanthanite,  harrisite, 
cantonite,  pyromorphite,  automolite,  zinc,  staurolite,  cyanite:  at  Ball- 
Ground,  spodumene. 

CLARK  Co. ,  near  Clarksville. — Gold,  zenotime,  zircon,  rutile,  cyanite, 
hematite,  garnet,  quartz. 

FANNIN  Co. — Staurolite!  chalcopyrite. 

HABERSHAM  Co. — Gold,  pyrite,  chalcopyrite,  galenite,  hornblende, 
garnet,  quartz,  kaolinite,  soapstone,  chlorite,  rutile,  iron  ores,  tourma- 
line, staurolite,  zircon. 

HALL  Co. — Gold,  quartz,  kaolin,  diamond. 

HEARD  Co. — Molybdite,  quartz. 

LEE  Co. — At  the  Chewacla  Lime  Quarry,  dolomite,  barite,  quartz 
crystals. 

LINCOLN  Co.—Lasulite!  rutile/  hematite,  cyanite,  menaccanite, 
pyrophyllite,  gold. 

LOWNDES  Co. — Corundum. 

LUMP  KIN  Co. — At  Field's  gold-mine,  near  Dahlonega,  gold,  tetrady- 
mite, pyrrhotite,  chlorite,  menaccanite,  allanite,  apatite. 

RABUN  Co.— Gold,  chalcopyrite,  muscomte,  beryl,  corundum. 

SPAULDING  Co. — Tetradymite. 

WASHINGTON  Co.,  near  Saundersville. —  Wavellite,  fire  opal. 

WHITE  Co.— Racoochee  Valley,  diamond. 

ALABAMA. 

BIBB  Co.,  Centreville. — Iron  ores,  marble,  barite,  coal,  cobalt. 

CHAMBERS  Co. — Near  La  Fayette,  steatite,  garnets,  actinolite,  chlo- 
rite; east  of  Oak  Bowery,  steatite. 

CHILTON  Co. — Muscovite,  graphite,  limonite,  rutile. 

CLEBURNE  Co. — At  Arbacoochee  mine,  gold,  pyrite,  and  three  miles 
distant  cyanite,  garnets;  at  Wood's  mine,  black  copper,  azurite,  chalco- 
pyrite,  pyrite. 


384         SUPPLEMENT  TO   DESCRIPTIONS   OP  SPECIES. 

CLAY  Co. — Steatite,  magnetite;  near  Delta  and  Ashland,  muscovite. 

COOSA  Co. — Tantalite,  gold,  muscovite,  cassiterite,  rutile,  mica;  near 
Bradford,  zircon,  corundum,  asbestus;  near  Rockford,  tantalite. 

RANDOLPH  Co.— Gold,  pyrite,  tourmaline,  muscovite;  at  Louina, 
porcelain  clay,  garnet. 

TALLADEGA  Co.  — Limonite. 

TALLAPOOSA  Co.,  at  Dudley ville.— Corundum,  margarite,  ripidolite, 
spinel,  tounnaline,  actinolite.  steatite,  asbestus,  chrysolite,  damourite, 
corundum  altered  to  tourmaline  (containing  a  nucleus  of  corundum),  at 
Dudleyville,  dudleyite. 

TUSCALOOSA  Co.— Coal,  galenite,  pyrite,  vivianite,  limonite,  calcite, 
dolomite,  cyanite,  steatite,  quartz  crystals,  manganese  ores. 

FLORIDA. 

NEAR  TAMPA  BAY. — Limestone,  sulphur  springs,  chalcedony, 
agate,  silicifled  shells  and  corals. 

KENTUCKY. 

ANDERSON  Co.  —Galenite,  barite. 

CLINTON  Co. — Geodes  of  quartz 

CRITTENDEN  Co.  —Galenite,  fluorite,  calcite. 

CUMBERLAND  Co. — At  Mammoth  Cave,  gypsum  rosettes!  calcite, 
stalactites,  nitre,  epsomite. 

FAYETTE  Co. — 6  m.  N.  E.  of  Lexington,  galenite,  barite,  witherite, 
blende. 

LIVINGSTON  Co.,  near  the  line  of  Union  Co.— Galenite,  chalcopyrite, 
large  vein  of  fluorite. 

MERCER  Co. — At  McAfee,  fluorite,  pyrite,  calcite,  barite,  celestite. 

OWEN  Co. — Galenite,  barite. 

TENNESSEE. 

BROWN'S  CREEK.— Galenite,  blende,  barite,  celestite. 

CLAIBORNE  Co. — Calamite,  galenite,  smithsonite,  chlorite,  steatite, 
magnetite. 

COCKE  Co.,  near  Bush  Creek.— Cacoxenite?  kraurite,  iron  sinter, 
stilpnosiderite,  brown  hematite. 

DAVIDSON  Co. — Selenite,  with  granular  and  snowy  gypsum,  or  ala- 
baster, crystallized  and  compact  anhydrite,  fluorite  in  crystals?  calcite 
in  crystals.  Near  Nashville,  blue  celestite  (crystallized,  fibrous,  and 
radiated),  with  barite  in  limestone.  Haysboro',  galenite,  blende,  with 
barite  as  the  gangue  of  the  ore. 

DICKSON  Co. — Manganite. 

JEFFERSON  Co.—Calamine,  galenite,  fetid  barite. 

KNOX  Co. — Magnesian  limestone,  native  iron,  variegated  marbles! 

MATJRY  Co.— Wavellite  in  limestone. 

POLK  Co.,  Ducktown  mines,  S.  E.  corner  of  State. — Melaconite, 
chalcopyrite,  pyrite,  native  copper,  bornite,  rutile,  zoisite,  galenite, 
harrisite,  alisonite,  blende,  pyroxene,  tremolite,  sulphates  of  copper  and 
iron  in  stalactites,  allophane,  rahtite,  chalcocite  (ducktownite),  chal- 
cotiichite,  azurite,  malachite,  pyrrhotite,  limonite. 


CATALOGUE   OF   AMERICAN   LOCALITIES   OF   MINERALS.    385 

ROAN  Co.,  E.  declivity  of  Cumberland  Mts. — Wavellite  in  lime- 
stone. 

SEVIER  Co.,  in  caverns.— Epsomite,  soda  alum,  nitre,  nitrate  of 
calcium,  breccia  marble. 

SMITH  Co. — Fluorite. 

SMOKY  MT.,  on  declivity. — Hornblende,  garnet,  staurolite. 

OHIO. 

BAINBRIDGE  (Copperas  Mt ,  a  few  miles  east  of  B.). — Calcite,  barite, 
pyrite,  copperas,  alum. 

CANFIELD  and  POLAND. — Gypsum! 

LAKEEKIE.— Strontian  Island,  celestite!  Put -in-Bay  Island,  celestite! 
sulphur!  calcite. 

MICHIGAN. 

BREST  (Monroe  Co.). — Calcite,  amethystine  quartz,  apatite,  celestite. 

GRAND  MARAIS. — Thomsonite  (lintouite). 

GRAND  RAPIDS. — Selenite,  fib.  and  granular  gypsum,  calcite,  dolo- 
mite, anhydrite. 

LAKE  SUPERIOR  MINING  REGION. — The  copper-mines  are  mostly 
between  Keweenaw  Point  and  Portage  Lake.  The  copper  occurs  in 
the  trap  or  amygdaloid,  and  in  the  associated  conglomerate  ;  and  in 
the  latter  (which  is  the  rock  of  the  Calumet  and  Hecla  mine)  the  ore  is 
distributed  finely  through  the  mass  of  the  rock.  Native  copper!  native 
silver!  chalcopyrite,  horn  silver,  tctrahedrite,  manganese  ores,  epidote, 
prehnite,  laumont.te,  datolite,  heulandite,  orthoclase,  analcite,  chabazite, 
compact  datolite,  chrysocolla,  mesotype  (Copper  Falls  mine),  leon- 
hardite  (ib.),  analcite  (ib.),  apophyllite  (at  Cliff  mine),  wollastonite  (ib.), 
calcite,  quartz  (in  crystals  at  Minnesota  mine),  compact  datolite.  or- 
thoclase (Superior  mine),  saponite,  melaconite  (near  Copper  Harbor, 
but  exhausted),  chrysocolla;  on  Chocolate  River,  galenite  and  sul- 
phide of  copper  ;  chalcopyrite  and  native  copper  at  Presque  Isle;  at 
Albion  mine,  domeykite;  at  Prince  Vein,  barite,  calcite,  amethyst;  at 
Albany  and  Boston  mine,  Portage  Lake,  prehnite,  analcite,  orthoclase, 
cuprite;  at  Sheldon  location,  domeykite,  whitneyite,  algodonite;  Quincy 
mine,  calcite,  compact  datolite.  At  the  Spur  Mountain  iron-mine 
(magnetite),  chlorite  pseudomorph  after  garnet;  Isle  Royalc,  datolite, 
prehnite. 

MARQUETTE. — Manganite,  galenite;  12  m.  W.,  at  Jackson  Mt.,  and 
other  mines,  hematite,  limonite,  gothite  !  magnetite,  jasper. 

MONROE.— Aragonite,  apatite. 

NEGAUNEE. — Manganite,  gothite,  hematite,  barite,  kaolinite. 

POINT  AUX  PEAUX  (Monroe  Co.). — Amethystine  quartz,  apatite, 
celestite,  calcite. 

SAGINAW  BAY. — At  Alabaster,  gypsum. 

STONY  POINT  (Monroe  Co.).— Apatite,  amethystine  quartz,  celestite, 
calcite. 

ILLINOIS. 

GALLATIN  Co.,  on  a  branch  of  Grand  Pierre  Creek,  16  to  30  m. 
from  Shawneetown,  down  the  Ohio,  and  from  half  to  eight  miles  from 
25 


386  SUPPLEMENT  TO    DESCRIPTIONS   OF   SPECIES. 

this  river. — Violet  fluorite  !  in  Carboniferous  limestone,  barite,  galenite, 
blende,  limonite. 

HANCOCK  Co. — At  Warsaw,  quartz  geodes  containing  caldte!  chal- 
cedony, dolomite,  blende!  brown  spar,  pyrite,  aragonite,  gypsum,  bitu- 
men. 

HARDIN  Co. —Near  Rqsiclare,  caldte,  galenite,  blende  ;  5  m.  back 
from  Elizabeth  town,  bog  iron  ;  one  mile  north  of  the  river,  between 
Elizabethtown  and  Rosiclare,  nitre. 

Jo  DAVIESS  Co.— At  Galena,  galenite,  calcite,  pyrite,  blende;  at 
Marsden's  diggings,  galenite  !  blende,  cerussite,  marcasite  in  stalactitic 
forms,  pyrite. 

QUINCY. — Calcite  !  pyrite. 

SCALES  MOUND. — Barite,  pyrite. 

INDIANA. 

LIMESTONE  CAVERNS  ;  Corydon  Caves,  etc. — Epsom  salt. 

In  most  of  the  southwest  counties,  pyrite,  iron  sulphate,  and 
feather  alum;  on  Sugar  Creek,  pyrite  and  iron  sulphate;  in  sand- 
stone of  Lloyd  Co.,  near  the  Ohio,  gypsum;  at  the  top  of  the  blue 
limestone  formation,  brown  spar,  calcite. 

LAWRENCE  Co. — Kaolinite  (=  indianaite),  Allophane,  limonite. 

MINNESOTA. 

NORTH  SHORE  OF  L.  SUPERIOR  (range  of  hills  running  nearly 
N.  E.  and  S.  W.,  from  Fond  du  Lac  Superieure  to  the  Kamanisti- 
queia  River  on  Thunder  Bay). — Scolecite,  apophyllite,  prehnite,  stilbite, 
laumontite,  Jieulandite,  harmotome,  thomsonite  (much  of  it  in  loose 
pebbles  on  shore  of  L.  Sup.,  between  Terrace  Point  and  Poplar 
River),  fluorite,  barite,  tourmaline,  epidote,  hornblende,  calcite,  quartz 
crystals,  pyrite,  magnetite,  steatite,  blende,  black  oxide  of  copper, 
malachite,  native  copper,  chalcopyrite,  amethystine  quartz,  chalce- 
dony, carnelian,  agate,  jasper  (in  the  debris  of 'the  lake  shore),  dog- 
tooth spar,  augite,  native  silver,  spodumene?  chlorite  ;  near  Pigeon 
Point,  graphite,  sphalerite,  chalcopyrite,  barite  ;  between  Pigeon 
Point  and  Fond  du  Lac,  near  Baptism  River,  saponite  (thalite)  in 
amygdaloid  ;  between  Split  Rock  R.  and  the  Great  Palisades,  anor- 
thite  rock  ;  in  Mesabi  Range,  magnetite  in  beds. 

PINE  Co. — Kettle  River  Trap  Range.  Epidote,  nail-head  calcite, 
amethystine  quartz,  calcite,  undetermined  zeolites,  saponite  ;  also 
copper  ores. 

STILL  WATER.  — Blende. 

FALLS  OF  THE  ST.  CROIX. — Malachite,  native  copper,  epidote,  nail- 
head  spar  (calcite). 

RAINY  LAKE. — Actinolite,  tremolite,  fibrous  hornblende,  garnet, 
pyrite,  magnetite,  steatite. 

WISCONSIN. 

BLUE  MOUNDS. — Cerussite. 

LAC  DE  FLAMBEAU  R. — Garnet,  cyanite. 

DOUGLAS  Co.,  Left-Hand  R.  (near  small  tributary). — Malachite, 


CATALOGUE   OF   AMERICAN   LOCALITIES   OF   MINERALS.    387 

chalcocite,  native  copper,  cuprite,  malachite,  niccolite,  tetraliedrite, 
epidote,  chlorite?  quartz  crystals. 

MINERAL  POINT  and  vicinity,  in  S.  W.  counties  of  Wisconsin. — 
Copper  and  lead  ores,  chrysocolla,  azurite!  chalcopyrite,  malachite, 
galetiite,  cerussite,  anglesite,  blende,  pyrite,  barite,  calcite,  marcasite, 
smithsonite!  (including  pseudomorphs  after  calcite  and  blende,  so- 
called  "dry-bone"),  calamine,  bornite,  hydrozincite;  at  Shullsburg, 
galenite!  blende,  pyrite;  at  Emmet's  digging,  galenite  and  pyrite. 

MONTREAL  RIVER  PORTAGE. — Galenite  in  gueissoid  granite. 

Penokee  and  Menomiuee  Iron  Ranges  S.  of  L.  Superior,  hematite, 
magnetite,  siderite,  actinolite,  garnet. 

SAUK  Co. — Hematite,  malachite,  chalcopyrite. 

IOWA. 

DUBUQUE  LEAD  MINES,  and  elsewhere. — Galenite!  calcite,  blende, 
black  oxide  of  manganese,  barite,  pyrite;  at  Swing's  and  Sherard's 
diggings,  smithsonite,  calamine;  at  Des  Moines,  quartz  crystals,  sele- 
riite;  Makoqueta  R.,  limonite;  near  Durango,  galenite;  7  in.  S.  of  Du- 
buqtie,  aragonite. 

CEDAR  RIVER,  a  branch  of  the  Des  Moines. — Selenitein  crystals,  in 
the  bituminous  shale  of  the  Coal  measures;  also  elsewhere  on  the 
Des  Moines,  gypsum  abundant;  argillaceous  iron  ore,  siderite. 

FORT  DODGE. — Cdestite,  gypsum,  pyrite. 

NEW  GALENA. — Octahedral  galenite,  anglesite. 

BENTONSPORT,  and  elsewhere  in  Southern  Iowa,  in  geodes. — Chal- 
cedony, quartz,  calcite,  dolomite,  pyrite,  kaolinite. 

MISSOURI. 

For  the  distribution  of  the  lead-mines  see  page  162.  Mine  la  Motte, 
and  some  old  openings  in  Madison  Co.,  afford  cobalt  and  nickel  ores 
abundantly.  At  Granby  and  other  mines  the  chief  zinc  ore  is  cala- 
mine, or  the  silicate  of  zinc,  while  in  Central  and  Southwestern  Mis- 
souri it  is  comparatively  rare,  and  smithsonite  is  the  prominent  ore, 
as  in  Wisconsin:  yet  calamine  is  the  most  abundant  zinc  ore  in  the 
State.  As  stated  by  A.  Schmidt,  the  zinc  ore  is  a  secondary  product 
to  sphalerite  (blende);  the  cerussite  often  coats  the  galenite,  or  has 
its  forms,  indicating  thus  its  source;  the  limonite  is  also  secondary, 
and  has  come  in  mainly  through  the  oxidation  of  pyrite.  At  the 
Granby  mines  the  calamine  is  called,  among  the  miners,  "Black 
.lack;"  blende,  "Resin  Jack;"  a  white  massive  smithsonite,  "White 
Jack;"  and  the  cerussite  is  the  "Dry  Bone;"  thus  departing  from 
ordinary  miners'  usage.  Gold  has  been  found  in  the  drift  sands  of 
Northern  Missouri  (Broadhead). 

ADAIR  Co.— GOthite  in  calcite. 

COLE  Co. — Old  Circle  Diggings  and  elsewhere,  barite!  galenite, 
chalcopyrite,  malachite,  azurite,  pyrite,  calcite,  calamine,  sphalerite. 

COOPER  Co. — Collin's  mine,  malachite,  azurite,  chalcopyrite, 
smithsonite,  galenite,  sphalerite,  limonite. 

CRAWFORD  Co.— At  Scotia  iron  bed,  hematite,  amethyst,  gOthite, 
malachite. 

DADE  Co. — Smithsonite. 


388  SUPPLEMENT  TO   DESCRIPTIONS   OF  SPECIES. 

FRANKLIN  Co. — Cove  mines,  Virginia  mines,  arid  mine  &  Burton, 
galenite,  cerussite,  anglesite,  barite;  at  Staton  copper-mine,  native 
copper,  chalcotrichite,  malachite,  azurite,  chalcopyrite. 

IRON  Co. — At  Pilot  Knob  and  Shepherd  Mountain,  hematite,  mag- 
netite, limonite,  manganese  oxide,  bog  manganese,  serpentine. 

JASPER  Co.  (adjoins  S.  E.  Kansas). — At  Joplin  mines  and  Oro- 
nogo,  galena!  sphalerite,  pyrite,  cerussite,  calamine,  dolomite,  bitu- 
men. 

JEFFERSON  Co. — Valle's,  galenite !  cerussile,  anglesite,  calamine, 
smithsonite,  sphalerite,  hydrozincite,  chalcopyrite,  malachite,  azurite, 
pyrite,  barite,  withe'rite,  limonite;  Frumet  mines,  galenite,  barite! 
smithsonite  f  pyrite,  limonite. 

MADISON  Co. — Mine  la  Motte,  galenite!  cerussite!  siegenite  (nickel- 
linnseite),  smaltite,  asbolite  (earthy  black  cobalt  ore),  bog  manganese, 
chalcopyrite,  malachite,  caledonite,  plumbogummite,  wolframite.  At 
Enistein  silver-mine,  galenite,  sphalerite,  wolframite,  pyrite,  quartz, 
muscovite,  actiuolite,  fluorite. 

MORGAN  Co. — Cordray  Diggings,  galena,  blende,  barite. 

NEWTON  Co.  (adjoins  S.  E.  Kansas). — Gran  by  mines,  galenite! 
cerussite,  calamine!  sphalerite,  smithsonite,  hydrozincite,  buratite, 
greenockite  (on  sphalerite),  pyromorphite.  dolomite,  calcite,  bitumen. 

ST.  FRANCOIS  Co. — Iron  Mountain,  hematite,  limonite,  apatite, 
tungstite,  wolframite,  mngnetite,  menaccanite. 

ST.  GENEVIETE  Co. — At  copper-mines,  chalcopyrite,  cuprite,  mala- 
chite, azurite,  covellite,  chalcocite,  bornite,  melaconite,  chalcanthite. 

ST.  Louis  Co. — Near  St.  Louis,  millerite  (in  the  Subcarboniferous 
St.  Louis  limestone,  largely  a  magnesian  limestone)  with  calcite! 
barite,  fluorite,  anhydrite,  gypsum,  strontianite. 

WASHINGTON  Co. — At  Potosi,  galenite,  cerussite,  anglesite,  barite. 

ARKANSAS. 

BATESVILLE.— In  bed  of  White  R,  above  Batesville,  gold. 

GREEN  Co. — Near  Gainesville,  lignite. 

HOT  SPRINGS  Co. — At  Hot  Springs,  wavellite,  thuringite,  novacu- 
lite;  Magnet  Cove,  brookitef  schorlomite,  eloeolite,  magnetite,  quartz, 
green  coccolite,  garnet,  apatite,  perofsklte  (hydrolitanite),  rutile ! 
ripidolite,  thomsouite  (ozarkite),  microcline,  cegirite,  protovermiculite, 
variscite. 

LAWRENCE  Co. — Smithsonite,  dolomite,  galenite;  nitre. 

MARION  Co. — Wood's  mine,  smithsonite,  hydrozincite  (marionite) 
galenite;  Poke  bayou,  braunite? 

MONTGOMERY  Co. — Variscite. 

PULASKI  Co.— Kellogg  mine,  10  m.  north  of  Little  Rock,  tetrahe- 
drite,  tennantite,  nacrite^  galenite,  blende,  quartz. 

SEVIER  Co. — Stibnite,  stibiconite,  bindheimite,  jamesonite. 

KANSAS. 

BROWN  Co.— Celestite. 

LINN  Co.,  and  elsewhere,  near  Missouri  line. — Lead  and  zinc  ores; 
on  Short  Creek,  galenite.  cerussile.  anglesite,  sphalerite,  calamine. 
WALLACE  Co.,  etc. — Gypsum  in  crystals. 


CATALOGUE   OF   AMERICAN   LOCALITIES  OF  MINERALS.    389 

DAKOTA. 

LAWRENCE  Co. — Redwater  Valley,  gypsum;  Bear  Lodge  range, 
gold. 

PENNINGTON  Co. — Etta  mine,  spodumene  !  cassiterite,  mica,  ovtlio- 
clase,  colambite!  leucopyrite,  scorodite,  olivenite.  The  Ingersoll 
claim,  10  m.  E.  of  Harney  Peak,  colambite,  tantaltte,  beryl;  Bald 
Mtn.,  pitcliblende,  torbernite  or  autunite. 

MONTANA. 

Mountains  in  "which  mines  occur  cover  the  southwestern  part  and 
the  western.  Commencing  on  the  west: 

SILVER  Bow  Co.  (formerly  southern  part  of  Deer  Lodge  Co.). — 
Summit  Valley  district,  in  veins  in  granite  or  related  rocks  (near 
Butte  Cily).  cerargyrile,  argentite,  chalcocite,  galenite,  silver,  gold,  mala- 
chite, chalcopyrite,  bornite,  pyrite,  cerussite,  freibergite,  sphalerite, 
manganese  ores;  Independence  distr.  and  Flint  Creek  distr.  (near 
Phillipsburg).  similar  ores  with  hubnerite. 

BEAVER  HEAD  Co.  (S.  of  Silver  Bow  Co.) — Near  Bannack  City, 
gold  and  tellurium  with  pyrite,  some  galenite,  nagyagite;  in  Bald 
Mtn.  and  Trapper  districts,  ores  of  lead  and  copper  with  silver  iii 
limestone. 

LEWIS  &  CLARKE  Co. — Silver  Creek,  in  veins  in  slates  and  slaty 
limestones,  gold,  with  some  ores  of  lead  and  copper  and  a  little  sil- 
ver; at  Helena,  gold- bearing  veins. 

JEFFERSON  Co.— Gold,  aurif.  pyrite,  some  galenite  and  silver. 

MADISON  Co. — Silver  Star  distr.,  gold  in  veins  in  gneiss,  some 
copper  and  silver  ores,  manganese  ores;  Mineral  Hill  distr.  and  N. 
of  Virginia  City,  in  gneiss,  argent  if.  galenite,  gold;  similar  ores  and 
rock  in  Hot  Springs  and  Red  Bluff  districts. 

WYOMING. 

ALBANY  Co.,  14  m.  S.  W.  of  Laramie  City. — Thenardite. 

LARAMIE  Co. — Near  Hartville,  chalcocite,  chiysocolla,  cuprite, 
malachite;  18m.  E.  of  Laramie  City,  graphite. 

SWEETWATER  Co. — Near  Atlantic  City,  S.  Pass  City,  and  Miner's 
Delight,  gold  in  quartz  veins;  near  Independence  Rock,  sodium  car- 
bonates (trona,  etc.). 

IDAHO. 

ALTURAS  Co.  (veins  mostly  in  granite). — Middle  Boise,  ruby  silver, 
native  silver,  gold,  cerargyrite.  siephanite.  argent  g.-ilenite,  argentite,  py- 
rite. chalcopyrite,  freibergite.  arsenopyrite.  sphalerite;  Hardscrabble, 
gold,  pyrite,  arsenopyrite.  Other  mines  at  Bomipnrte  (gold  and  silver 
ores),  Mineral  Hill  (silver  ores),  Queen's  River  (gold  and  silver  ores), 
Red  Warrior  (gold  and  silver  ores).  Rocky  Bar  (gold),  Sawtooth 
(silver  ores);  at  Jay  Gould  mine,  with  the  other  ores,  native  lead. 

BOISE  Co.  (veins  in  granite). — Banner,  ruby  silver  ore,  cerargyrite, 
pyrite;  gold  at  Canon  Creek,  Gambrinus,  Granite,  Shaw's  Mountain, 
etc. 


390  SUPPLEMENT  TO   DESCRIPTIONS  OF  SPECIES. 

IDAHO  Co. — Warren's  Camp  (veins  in  slate  and  limestone),  gold, 
silver,  cerargyrite,  etc.,  scheelite  with  gold  (Charity  mine). 

LEMHI  Co. — Bay  Horse  (veins  in  slate),  argent,  galenite,  chalcocite, 
rerargyrite,  bromy'rite,  malachite,  gold;  Yankee  Fork,  gold,  pyrite, 
chalcopyrite,  stephanite? 

OWHYHEE  Co. — (Veins  in  granite,  metamorphic,  and  other  rocks 
intersected  by  dikes  of  igneous  rocks,  situated  near  Silver  City,  on 
the  Jordan  li )  Carson,  gold,  silver,  cerargyrite,  etc.;  Wagoutowu, 
gold,  argentite,  pyrite,  stephanite;  on  Jordan  R.,  stream  tin.  Gold 
also  in  Oneida  Co.,  at  Cariboo  and  Iowa  Bar,  Kootenai,  Nez  Perce, 
Shoshone  and  Washington  Cos. ;  Bear  Lake  Co.  (S.  E.  corner  of 
Idaho),  near  Soda  Spring,  soda  carbonate,  salt,  sulphur. 

COLORADO. 

BOULDER  Co.  (eastern  part,  between  Jamestown  and  Magnolia, 
noted  for  rich  tellurides  with  tellurium). — Central  distr.  (Smuggler 
mine,  etc.,  in  mica  schist  or  gneiss);  tellurides,  pyrite;  Gold  Hill  distr. 
(Red  Cloud,  etc.,  mines),  gold,  tellurides  of  gold,  silver,  mercury, 
pyrite,  sphalerite,  chalcopyrite;  Magnolia  distr.,  tellurides,  etc.,  tel- 
lurium ores  of  the  range  including  allaite,  hessite,  petzite,  sylvanite, 
tellurite,  native  tellurium,  calaverite,  coioradoite,  melonite,ferro-lellurite, 
magnolite,  and  the  associated  ores,  argentite,  amalgam,  native  mer- 
cury, native  bismuth,  bismuthinite,  bismutite,  pyrargyrite,  iodyrite, 
kobellite,  schirmerite,  hiibnerite;  Sunshine  and  Sugar  Loaf  districts 
afford  tellurides;  Ward  distr.,  aurif.  pyrite  and  chalcopyrite,  gold; 
Grand  Island  distr.  (Caribou  mine),  argentif.  galenite,  chalcopyrite, 
pyrite,  gold,  sphalerite;  Sugar-Loaf  distr.,  chalcocite,  pyrrhotite, 
manganesian  garnet. 

CHAFFEE  Co. — Arrow  mine,  jarosite  with  turgite;  gold  gravels  (at 
Cash  Creek,  etc.);  Monarch  distr.,  cerussite,  brochantite,  etc.;  near 
Mt.  Anteros,  in  Arkansas  Valley,  beryl* ;  at  Salida,  garnets;  at 
Nathrop,  in  cavities  in  rhyolyte,  topaz,  garnet. 

CLEAR  CREEK  Co.— Georgetown,  arirentif.  galenite,  native  silver, 
pyrargi/rite,  argeutite,  tetrahedrite,  pyromorphite,  sphalerite,  azurite, 
aragonite,  barite,  fluorite,  polybasite  (Terrible  Lode),  mica;  Trail 
Creek,  garnet,  epidote  ;  Freeland  Lode,  tetrahedrite,  tennantite, 
anglesite,  caledouite,  cerussite,  tenorite,  siderite,  azurite,  minium; 
Champion  Lode,  tenorite,  azurite,  chrysocolla,  malachite  ;  Gold  Belt 
Lode,  viviauite;  Coyote  Lode,  malachite,  cyanotrichite;  Virginia 
district,  galenite,  chalcopyrite,  pyrite,  tetrahedrite. 

CUSTER  Co. — Near  Rosita  and  Silver  Cliff,  6  m.  W.  of  R.,  argent, 
galenite,  sphalerite,  pyrite,  chalcopyrite,  annabergite,  carrying  silver 
and  gold^ores  at  the  latter  place  incrusting  fragments  or  pebbles  of 
country  rock,  calamine,  smithsonite,  jamenonite,  tetrahedrite,  tellurites 
of  silver  and  gold,  niccolite  ;  also  at  the  Racine  Boy  mine,  cerussite, 
cerargyrite;  at  the  Gem  mine,  13  m.  N:  of  Silver  Cliff,  niccolite, 
bornite,  pyrite;  E.  slope  of  Sangre  de  Cristo,  Verde  mine,  chalcopyr- 
ite, tetrahedrite,  pyrite. 

EL  PASO  Co.  (includes,  in  W.  part,  Pike's  Peak).— 25  m.  N.  of 
Pike's  Peak,  near  Platte  (Devil's  Head)Mtn.,  topaz !  microcline,  albite, 
phenacite,  smoky  quartz,  gdthite,  fluorite,  cassiterite,  allanite,  gadolin- 


CATALOGUE   OF   AMERICAN   LOCALITIES   OF  MINERALS.    391 

ite;  near  Florissant,  12  m.  N.  W.  from  the  Peak,  microcline !  topaz! 
on  Elk  Creek,  phenacite,  microcline  (amazon  stone),  smoky  quartz! 
amethyst!  albite,  fluorite,  zircon  !  columbite  !;  south  of  Manitou,  in 
Crystal  Park,  topaz,  phenacite,  zircon.  Near  Pike's  Peak  toll-road, 
W.  of  Cheyenne,  N.  E.  base  of  St.  Peter's  Dome,  in  quartz  vein, 
p'rcon,  astrophyllite,  arfvedsonite,  cryolite,  thomsenolite,  gearksutite, 
prosopite,  ralstonite,  elpasolite,  tysonite,  bastuaesite;  in  another  vein, 
prosopite,  zircon,  fluorite,  kii()liiiite,yellowish  mica,  cryolite;  between 
Colorado  Springs  and  Canon  City,  barite;  Garden  of  the  Gods,  cel- 
cstite,  rhodochrosite. 

GILPIN  Co.— Veins  in  gneiss  or  granite.  Near  Central  City, 
Gregory  dist.,  about  Black  Hawk  (Bobtail  mine,  etc.),  chalcopyrite, 
pyrite,  sphalerite,  galenite,  enargite  and  fluorite;  in  Willis  Gulcb, 
uraninite  (Wood  mine);  Nevada  district  (next  west  of  Gilpiu),  galen- 
iie,  chalcopyrite,  pyrite,  sphalerite,  etc.;  Russell  dist.  (in  Russell 
Gulch),  galenite,  tetrahedrite,  enargite,  pyrite,  fluorite,  chalcopyrite, 
pyrite,  epidote. 

GUNNISON  Co.  (W.  of  Sawatch  Mis.  and  S.  of  Elk  Mts.).— Ruby 
district,  ruby  silver,  arseuopyrite,  in  quartz  vein;  on  Brush  Creek, 
W.  base  of  Teocalli  Mtn.,  nickeliferous  lollingite,  smaltite,  marcasite, 
native  silver,  proustite,  pyrargyrite,  argentite,  galenite,  chalcopyrite, 
in  a  gangtie  of  siderite,  barite,  andcalcite. 

HINSDALE  Co. — Lake  City,  HotchkissLode,  petzite,  calaverite ;  Lake 
district,  argent,  galenite,  freibergite,  sphalerite,  aurif.  chalcopyrite, 
argentobisinutite;  Park  district,  stephanite,  galenite,  chalcopyrite; 
Galena  district,  argent,  galenite,  freibergite,  sphalerite,  chalcopyrite, 
rhodocrosite,  stephanite,  ruby  silver,  gold,  silver. 

HUERFANO  Co.— Southern  border,  N.  slope,  W.  Spanish  Peaks, 
galenite,  pyrite,  chalcopyrite,  tetrabedrite. 

JEFFEKSON  Co. — Near  Golden,  on  Table  Mtn.,  leucite,  analcite,  apo~ 
pJiyllite,  chabazite,  levynite,  laumontite,  mesolite,  natrolite,  scolecite, 
stilbite,  thomsonite,  calcite,  aragonite;  Turkey  Creek,  columbite. 

LAKE  Co,  (between  Mosquito  Mts.  and  Sawach  Range,  both 
Archaean  at  centre),  supplying  three  fourths  of  the  silver  and  gold  of 
Colorado,  with  Paleozoic  rocks  between,  and  great  eruptive  forma- 
tions.— About  Leadville  (or  California  mining  district),  on  W.  portion 
of  Mosquito  Range,  and  mostly  confined  to  Lower  Carbonif.  limestone, 
and  generally  beneath  eruptive  rocks,  silver,  galenite,  cerussite,  angle- 
site,  cerargyrite,  bromyrite,  iodyrite,  embolite,  aurif.  chalcopyrite  and 
pyrite,  sphalerite,  pyromorphite,  minium,  pyrolusite.  rlwdochrosite,  cala- 
mine,  sphalerite,  bismuthinite,  bismutite,  gold,  dechenile(in  Morning 
Star  and  Evening  Star  mines),  kobellite  (Printer  Boy  hill);  Florence 
mine,  bismutite;  Ute  and  Ule  mines,  stephanite,  galenite,  sphalerite,  chal- 
rocite  ;  Homestake  Peak,  N.  W.  corner  of  county,  argent,  galenite ; 
Golden  Queen  mine,  tcheelite,  gold. 

LA  PLATA  Co.  (8.  of  San  Juan  Co.).— S.  side  of  La  Plata  Mts.,  2£ 
m.  N.  of  Parrott  City,  aurif.  pyrile,  galenite,  tetrahedrite,  cosalite 
(Comstock  mine). 

OURAY  Co.  (W.  of  N.  end  of  Hinsdale  Co.,  with  Uncompaghgre 
Mts.  between). — Near  Ouray,  argent,  galenite,  some  freibergite,  chal- 
copyrite, pyrite,  hubnerite,  rhodochrosite;  at  National  Bell  miqe,  kao- 
linite  in  cryst. 


392  SUPPLEMENT  TO   DESCRIPTIONS  OF  SPECIES. 

PARK  Co. — Mines  chiefly  along  its  northwest  side,  on  the  E.  slope 
of  the  Mosquito  range,  in  the  Paleozoic  region  of  its  eastern  side,  near 
eruptive  rocks.  In  N.  part  Hall's  Valley,  veins  in  gneiss,  galenite, 
tetrahedrite,  enargite,  pyrite,  sphalerite,  fluorite,  barite,  ilesite;  near 
Grant,  Baltic  Lode,  begeerite,  N.  W.  of  Alma,  on  Mts.  Bross  and  Mt, 
Lincoln,  in  Carbon  if.  limestone,  argent,  galenite,  cerussite,  anglesite, 
cerargyrite,  barite,  manganese  oxide;  in  Buckskin  Gulch  (between 
these  mts.),  in  Cambrian  quartzyte,  aurif,  pyrites,  gold,  silver,  galenite; 
Sweet  Home  and  Tanner  Boy  mines,  S.  W.  side  of  Mt.  Bross,  in 
Archaean,  rhodochrosite  in  the  latter;  in  Mosquito  Gulch,  south  of 
Alma,  near  Horseshoe,  argent,  galenite,  cerussite.  Mines  of  Lincoln 
Mtn.  at  13.00.0  to  14,000  ft.  elevation. 

PITKIN  Co.  (between  Elk  Mts.  and  Sawatch  Range).— At  Indepen- 
dence, on  W.  slope  of  Sawatch,  on  the  Roaring  Fork,  in  Archaean,  and 
west  of  Aspen,  on  the  K  E.  slope  of  Elk  Mts.,  Alpine  Pass,  -Pitkin 
and  Tin  Cup  mines,  in  limestone,  cerussite,  cerargyrite,  cuprite. 

Rio  GRANDE  Co. — At  head  of  Rio  Ahimosa,  near  Summitville,  E. 
part  of  San  Juan  Mts.,  gold,  in  quartz  veins,  euanrite. 

SAN  JUAN  Co.  (S.  and  S.  E.  of  E.  end  of  San  Miguel  Co.,  crossed 
by  the  San  Juan  Mts.). — An i mas  and  Eureka  districts,  about  Baker's 
Park  and  Silverton,  i'reibergite,  argent,  galenite,  cerussite,  azurite, 
malachite,  chalcopyrite,  clmlcocite,  covellite,  barite,  zunyite,  and 
guitermanite  (at  Zuni  mine);  Red  Mtu.  dist.  (Brobdignng  mine), 
einkenite,  enargite,  tennantite.  htlbncrite  (Adams'  mine);  Poughkeep- 
sie  Gulch,  Alaska  mine,  alaskaite,  chalcopyrite,  tetrahedrite,  barite, 
tellurite:  Yankee  Girl  mine,  cosalite. 

SAN  MIGUEL  Co.  (S.  of  Ouray  Co.,  eastern  part  including  N.  por- 
tion of  San  Juan  Mts.). — At  Sneffels  (near  Mt.  Sneffels),  freibergite. 
stephanite,  argent,  galenite,  cerussite,  etc. ;  Upper  San  Miguel  and 
Iron  Springs  districts,  similar  ores;  at  Telluride,  galena,  stephanite, 
chalcopyrite,  gold,  electrum. 

SUMMIT  Co. — In  southeastern  part,  on  W.  slope  of  Archaean 
"Front  Range,"  near  Montezuma  and  Peru,  argent,  galenite,  etc. ; 
in  southern  part,  near  headwater  of  Blue  R.,  S.  of  Breckenridge,  near 
Robinson,  on  Quandary  Peak,  etc.,  in  limestone,  argent,  galenite, 
pyrite,  native  gold,  sphalerite;  Chalk  Mtn.,  junction  of  Summit  Park 
and  Eagle  Cos.,  in  rhyolyte  (nevadite),  sanidin,  topaz  in  small  crys- 
tals; Snake  River  district,  alabandite  (Queen  of  the  West  mine),  with 
rhodocrosite. 

UTAH. 

The  silver-mines  are  mostly  in  limestone,  with  eruptive  rocks  in 
the  vicinity,  and  argentif.  galenite,  cerussite,  anglesite,  cerargyrite, 
etc.,  the  common  ores.  The  veins  in  slate  or  quartzyte  in  part 
carry  copper  ores.  There  are  also,  as  shown  first  by  Prof.  Newbeny. 
sandstones  in  Southern  Utah  impregnated  by  ores  (cerargyrite,  etc.) 
over  large  regions. 

BEAVER  Co. — Bradshaw,  cerussite,  cuprite,  malachite,  aragonite; 
San  Francisco,  cerussite,  anglesite,  galenite,  dufrenoysite,  proustite, 
pyrargyrite,  cerargyrite,  argentite,  barite;  Star,  cerussite,  cerargyrite, 
malachite. 


CATALOGUE   OF   AMERICAN   LOCALITIES   OF   MINERALS.    393 

IRON  Co. — Coyote  district,  orpiment,  realgar,  thin  layer  in  strata 
under  lava. 

JUAB  Co. — Tintic  district,  galenite,  anglesite,  cerussite,  malachite,, 
bornite,  cuprite,  bismuthite,  olivenite,  conichalcite,  chenemxite,  jarosiie, 
calcium  arsenate  (at  American  Eagle  mine);  enargite  (at  Mammoth, 
Shoebridge,  and  Dragon  mines);  40  m.  N.  of  Sevier  Lake  and 
40  m.W.  N.  W.  of  Deseret,  topaz  in  rhyolyte,  with  garnet  and  sani- 
din. 

PIUTE  Co. — Ohio,  galenite,  cerussite,  malachite,  chalcopyrite,  chnl- 
cocite,  tetraliedrite;  Mt.  Bald3r,  galenite,  cerussite,  angleaite,  wulfenite, 
argentite  (Pluto  mine);  Marysvale,  onofrite.  Tiemannite  (at  Lucky 
Boy  mine). 

SALT  LAKE  Co. — Big  Cottonwood,  galenite,  cerussite,  anglesite,  mala- 
chite, with  sometimes  pyrolusite;  Little  Cottonwood,  at  Emma  and 
other  mines,  same,  with  sometimes  argentite,  dufrenoysite,  wulfenite, 
linarite,  chalcopyrite,  enargite  (at  Oxford  and  Geneva  mine);  West 
Mountain,  same  ores,  with  argentite,  pyrargyrite,  rhodochrosite, 
barite  at  Queen  mine;  binnite,  etc.,  at  Tiewaukee  mine;  dufrenoy- 
site, etc.,  at  Winnamuck  mine;  Butterfield  Canon,  orpiment,  realgar, 
mallardite,  iuckite;  Wasatch  Mts.,  head-waters  of  Spanish  Fork, 
ozocerite  in  beds. 

SUMMIT  Co. — Uintah,  cerussite,  anglesite,  cerargyrite,  tetrahedrite, 
argentite,  malachite. 

TOOELE  Co. — Camp  Floyd,  stibnite,  etc. ;  Ophir,  galenite,  cerussite, 
malachite,  chalcopyrite,  cerargyrite;  Rush  Valley,  same  ores :  American 
Fork  and  Silver  Lake,  same  ores. 

WASATCH  Co. — Blue  Ledge  and  Snake  Creek,  galenite,  cerussite, 
pyromorphite,  sphalerite,  etc. 

WASHINGTON  Co. — Harrislmrg,  in  sandstone  and  clay,  native  silver, 
cerargyrite,  argentite;  fossil  plants  sometimes  replaced  by  silver  and 
cerargyrite. 

NEW  MEXICO. 

DONA  ANA  Co. — At  Lake  Valley,  in  the  Sierra  mines,  in  limestone, 
argent,  galenite,  cerussite,  cerargyrite,  embolile,  iodyrite,  manganese 
ores,  vanadinite,  endlichite,  descloizite.,  native  silver,  pyrolusite,  mau- 
ganite,  fluorite,  apatite:  Victoria  mine,  40  m.  below  Nutt,  anglesite; 
at  Kingston,  iu  Black  Range,  aragonite. 

Grant  Co. — S.  W.  corner  of  N.  Mexico,  adjoining  Arizona. — In  N. 
E.  corner  of  county,  S.  part  of  Mimbrcs  Mtn.,  E.  of  Silver  City,  ores 
in  limestone  or  shale,  argentif.  galenite,  cerargyrite,  argentite,  native 
silver,  barite,  fluorite;  Santa  Rita  mines,  in  porphyry  near  limestone, 
native  copper,  tenorite;  Pinos  Altos  Mtn.,  N.  of  Silver  City,  argent, 
galenite.  cerargyrite,  cerussite,  argentite,  silver,  gold,  chalcopyrite, 
barite;  Burro  Mts.,  S.  W.  of  Silver  City,  similar  ores;  in  S.  W.  part 
of  Co.,  near  Barney's  Station  and  Warren,  Virginia  distr.,  veins  of 
quartz,  with  argent,  galenite,  cerargyrite,  native  silver. 

SANTA  FE  Co.— LosCerillos  distT,  22  in.  S.  W.  of  Santa  Fe,  in  L. 
C.  Mts.,  turquois  in  trachyte,  argent,  galenite,  cerussite,  wulfenite, 
manganese  ores;  Silver  Bute  distr.,  in  quartzyte,  gold,  pyrite,  azurile, 
malachite,  cuprite,  chalcopyrite,  bournouite,  chrysocolla. 


394  SUPPLEMENT  TO    DESCRIPTIONS   OP   SPECIES. 

SIERRA  Co.  (S.  of  Socorro  Co.). — Near  Hillsboro',  gold  in  veins 
and  placers. 

SOCORRO  Co.  (N.  E.  of  Grant). — 3  m.  from  Socorro,  in  Socorro 
Mis.,  cerargyrite,  vanadinite,  vanadiferous  mimetite,  barite;  in  Magda- 
lena  Mts.,  27  m.  W.  of  Socorro,  galenite,  cerussite,  anglesite,  cala- 
mine,  sphalerite;  Oscuro  Mts.  toE.,  chalcopyrite,  azurite,  malachite, 
associated  with  fossil  wood  and  plants;  at  Grafton,  gold,  cerussite, 
chalcocite,  boruite,  malachite,  chalcopyrite,  cerargyrite,  amethyst. 

ARIZONA. 

APACHE  Co.— Copper  Mountain,  chalcocite,  azurite,  melaconite, 
sphalerite,  pyrite;  and  at  Greenlee  Gold  Mountain,  chalcocite,  mala- 
chite, cuprite,  auriferous  gravel. 

COCHISE  Co.  (S.  E.  corner  of  State). — 20  m.  from  Tombstone, 
turquois  (chalchuite);  Bisbee,  malachite,  aurichalcite. 

GRAHAM  Co. — Clifton,  dioptase,  cuprite,  azurite,  chrysocolla. 

MARICOPA  Co. — Vulture  district  (and  on  borders  of  Yavapai  Co.), 
at  Farley's  Collateral  mines  (20  m.  N.  of  V.),  vanadinite,  chrysocolla, 
crocoite,  descloizite,  gold;  at  Phenix  and  other  mines  near  the  last, 
vanadinite,  gold,  vauquelinite,  crocoite,  pho3nicochroite,  silver,  sphaler- 
ite, argentite,  pyrargyrite;  Tip  Top  (at  Humbug,  in  Yavapai  Co.), 
east  of  last,  silver,  sphalerite,  argentine,  pyrargyrite;  2£  m.  S.  W.  of 
Fort  Verde,  large  bed  of  thenardite;  Globe  district  (partly  in  Final 
Co.),  argentite,  stromeyerite,  boruite,  chalcopyrite,  chalcocite,  mala- 
chite, cuprite,  manganese  ore,  barite;  Jerome,  gerhardtite. 

MOHAVE  Co.  (veins  in  granitoid  rocks). — Hualapai  district,  galenite, 
cerussite,  sphalerite,  ruby' silvers,  chalcopyrite,  pyrite;  Maynard,  gale- 
nite, stephanite,  argentite,  silver,  gold,  cerargyrite,  sphalerite;  Cedar 
Valley  district  (Congress  and  other  mines),  galenite,  ruby  silvers,  tet- 
rahedrite,  cerargyrite,  sphalerite,  pyrite;  Owens  district  (Signal  mine, 
etc.),  galenite,  argentite,  etc. 

PIMA  Co. — Many  of  the  veins  in  limestone,  which  is  probably  Car- 
boniferous, near  eruptive  rocks,  and  others  in  granite;  Oro  Blanco, 
near  Mexican  line,  argentif.  galenite,  cerussite,  malachite,  cerargyrite, 
freibergite,  etc.;  Arivaca,  Tubac,  similar  ores;  Tombstone,  galenite, 
cerargyrite,  silver,  gold,  cerussite,  malachite,  pyrolusite;  similar  ores  at 
Hartford,  Meyers,  etc. ;  near  Tucson,  copper  ores;  Turquois  (western 
part  of  county,  Ajo  mine  in  quartzyte),  chalcopyrite,  bornite,  mala- 
chite; and  Defiance  mine  in  limestone,  argent,  gulenite,  cerussite. 

FINAL  Co.— Globe  (Stonewall  Jackson,  etc.,  mines).  See  MARI- 
COPA  Co. — Pioneer  (Silver  King,  El  Capitan,  and  other  mines),  silver, 
freibergite,  argentite,  stephanite,  stromeyerite,  chalcopyrite,  bornite, 
malachite,  azurite,  galena,  sphalerite,  pyrite,  polybasile,  miargyrite, 
pyrargyrite  (last  three  from  El  Capitau);  vanadinite  and  wult'enite 
(Black  Prince  mine,  Pioneer  distr.). 

YAVAPAI  Co. — Big  Bug  (Silver  Belt  mine,  in  gneiss  or  granite), 
galenite,  cermsite,  cerargyrite,  barite,  calcile;  Jerome,  gerhardtite.  See 
further,  MARICOPA  Co. 

YUMA  Co. — Castle  Dome,  in  gneiss,  argent,  galenite,  anglesite,  ce- 
russite,  fluorite,  vanadinite,  wulfenite,  mimetite;  Silver  district  (veins 
iu  gneiss  and  mica  slate,  Hamburg,  Princess,  Red  Cloud,  etc.,  mines), 
argent,  galenite,  anglesite,  cerussite,  wulfenite,  vanadinite,  fluorite. 


CATALOGUE   OF  AMERICAN   LOCALITIES   OF  MINERALS.    395 

NEVADA. 

The  chief  mining  regions  of  Nevada  nffording  silver  and  partly 
gold  are  either  veins  connected  obviously  with  igneous  eruptions,  as 
the  Comstock  Lode;  veins  in  granitic  or  metamorphic  rocks,  as 
the  Austin  mines;  and  deposits  or  supposed  veins  in  limestone,  either 
of  the  Cambrian  or  later  age,  as  the  Eureka  and  White  Pine  mines. 

CHURCHILL  Co. — Ragtown,  gay-lmsite,  trona,  halite;  Cottonwood 
Campus,  niccolite,  annabergite. 

ELKO  Co. — Tuscarora,  veins  in  igneous  rocks,  stephanite,  cerargy- 
rite, ruby-silver  ores  (proustite  and  pyrargyrite),  argentite,  stephanite, 
chalcopyrite,  pyrite,  sphalerite,  chrysocolla. 

ESMERALDA  Co. — In  metamorphic  slates  and  schists,  or  in  granite, 
•which  are  intersected  by  igneous  rocks,  at  Columbus,  gold,  cerargy- 
rite,  tetrahedrite,  galenite,  pyrite,  sphalerite,  pyrolusite,  turquois, 
stetefeldite;  also  gold  in  Esmeralda  and  Wilson  in  quartz;  silver,  ga- 
lenite, and  chalcopyrite  in  Oneota,  in  mica  schist;  Alum,  12  m.  N.  of 
Silver  Creek;  at  Aurora,  fluorite,  stibnite;  near  Mono  Lake,  native 
copper  and  cuprite,  obsidian:  Thiel  Salt  Marsh,  ulexite,  borax,  corn- 
men  salt,  tlienardite  ;  Columbus  district,  ulexite,  thenardite,  sulphur; 
Walker  Lake,  gypsum,  hematite. 

EUREKA  Co. — Eureka,  Ruby  Hill,  etc.,  in  Lower  Cambrian  lime- 
stone, gold,  silver,  cerussite,  galenite,  anglesite,  mimetite,  iculfemte, 
limonite,  aragonite;at  Cortez,  cerargyrite,  tetrahedrite,  silver,  etc. 

HUMBOLDT  Co.— Veins  in  Mesozolc  slates,  at  Paradise;  stiver,  ce- 
rargyrile,  tetrahedrite,  pyrargyrite,  proustite,  stepJianite,  arsenopyrite, 
chalcopyrite,  sphalerite,  pyrite;  between  slate  and  granite  at  Winne- 
mucca,  sulphides  and  antimonial  sulphides  of  lead,  with  silver,  jame- 
sonite,  Btibnite,  bournonite;  near  Lovelock's  Station,  erythrite,  mil- 
lerite,  asbolite. 

LANDER  Co. — At  Austin,  near  Reese  River,  in  the  Toyabe  Range, 
which  has  a  granitic  axis  flanked  by  Paleozoic  strata,  and  the  veins 
in  the  granite  of  Lander  Hill  (yielding  $1,000,000  of  silver  annually), 
situated  near  the  western  edge  of  the  Paleozoic  area  of  the  eastern 
half  of  the  Great  Basin,  tetrahedrite,  pyrargyrite,  proustite,  cerargyrite, 
stephanite,  polybasite,  rhodochrosite,  embolite,  chalcopyrite,  pyrite, 
galenite,  azurite,  whitneyite;  also  mines  at  Lewis  of  ruby  silver, 
etc.,  in  quartzyte;  and  at  Battle  Mountain,  of  galenite  in  Paleozoic 
slate. 

LINCOLN  Co. — Bristol,  galenite,  cerussite,  etc. ;  Eldorado,  cerargy- 
rite, stromeyerite;  Jack-Rabbit,  argentif.  galenite,  cerussite,  cuprite, 
malachite;  Ely,  gold,  cerargyrite,  galenite,  sphalerite,  pyrite. 

NYE  Co. — At  Belmont  (vein  in  Silurian  slate),  argent,  galenite, 
stephanite,  pyrite,  chalcopyrite,  anglesite,  stetefeldite;  Morey,  ruby 
silver  and  other  arsenical  and  autimonial  ores,  etc. ;  Tybo,  galenite, 
cerargyrite,  etc.;  Union,  cerargyrite,  galenite,  sphalerite,  etc.;  Dow- 
uieville,  anglesite,  cerussite,  wulfenite,  sphalerite,  pyrite. 

STOREY  andLYON  Cos. — Mines  of  the  Comstock  Lode,  gold,  native 
silver,  argentite,  stephanite,  polybasite,  ruby  silver  ores,  tetrahedrite, 
cerussite,  wulfenite,  kilstelite,  etc. 

WHITE  PINE  Co. — While  Pine,  in  Devonian  limestone,  cerargyrite; 
at  Ward,  same  limestone,  sulphautimouides  (probably  strorneyerite), 
pyrite,  etc. ;  at  Cherry  Creek,  copper  carbonate,  sulphides,  etc. 


396  SUPPLEMENT  TO   DESCRIPTIONS  OF   SPECIES. 

CALIFORNIA. 

The  principal  gold  regions  are  in  Fresno,  Mariposa,  Tuolnmnc, 
Calaveras,  El  Dorado,  Placer,  Nevada,  Yuba,  Sierra,  Butte,  Plumas, 
Shasta,  Siskiyou,  and  Del  Norte  counties,  al though  gold  is  found  in 
almost  every  county  of  the  State. 

The  copper-mines  are  principally  at  or  near  Copperopolis,  in  Cala- 
veras County;  near  Genesee  Valley,  in  Plumas  County;  near  Low 
Divide,  in  Del  Norte  County;  on  the  north  fork  of  Smith's  River; 
at  Soled  ad,  in  Los  Angeles  County. 

The  mercury -mines  are  at  or  near  New  Almaden  and  North  Al- 
maden.  in  Santa  Clara  County;  at  New  Idria  and  San  Carlos,  Mon- 
terey County;  in  San  Luis  Obispo  County;  at  Pioneer  mine,  and 
other  localities  in  Lake  County;  in  Santa  Barbara  County. 

A  LAMBDA  Co. — Diabolo  Range,  magnesite. 

ALPINE  Co. — Morning  Star  mine,  enargile,  stephanite,  polybasite, 
barite,  quartz,  pyrite,  tetrahedrite.  pyrargyrite. 

AMADOU  Co. — At  Volcano,  chalcedony,  hyalite;  lone  Valle}r, 
chalcopyrite,  ionite,  lignite;  Fiddletown,  diamond;  gold  at  several 
mines  with  chalcopyrite,  pyrite,  galenite. 

BERNARDINO  Co. — At  Borax  works,  hanksite! 

BUTTE  Co.  —  Cherokee  Flat,  diamond,  platinum,  iridosmine, 
chromite,  zircon. 

CALAVERAS  Co. — Copperopolis,  and  Campo  Seco,  chalcopyrile, 
malachite,  azurite,  serpentine,  picrolite,  native  copper;  near  Murphy's, 
jasper,  opal;  albite,  with  gold  and  pyrite;  Mellones  mine,  cakwerite, 
petzite. 

COLUSE  Co. — Butte  City,  Gagnon  mines,  goslarite,  wnrtzite. 

DEL  NORTE  Co. — Crescent  City,  agate,  carnelian;  Low  Divide, 
chalcopyrite,  boruite,  malachite;  on  the  coast,  iridosmine,  platinum, 
gold  in  gravel,  zircon,  diamond. 

EL  DORADO  Co. — Pilot  Hill,  chalcopyrite;  near  Georgetown,  hes- 
site,  from  placer  diggings;  Roger's  Claim,  Hope  Valley,  granular 
garnet,  in  copper  ore;  Coloma,  chromite;  Placerville,  gold;  Granite 
Creek,  roscoelite,  gold;  Forest  Hill,  diamond;  Cosumnes  mine, 
molybdenite. 

FRESNO  Co. — Chowchillas,  andalusite ;  King's  River,  bornite; 
New  Idria,  cinnabar. 

HUMBOLDT  Co. — Cryptomorphite. 

INYO  Co. — Inyo  district,  galenite,  cerussite,  anglesite,  barite,  atnca- 
mite,  calcite,  grossular  garnet!  vesuvianite,  datolite;  Pnnamint, 
tetrahedrite,  stromeyerite;  Kenrsarge  mine,  cerussite.  tetrahedrite, 
cerargyrite,  argentite;  Cerro  Gordo,  wulfenite,  cerussite,  anglesite, 
polybasite. 

KERN  Co. — Green  Monster  mine,  cuproscheelite. 

LAKE  Co. — Borax  Lake,  borax!  sassolite,  glauberite ;  Pioneer 
mine,  cinnabar,  native  mercury,  selenide  of  mercury;  near  the  Gey- 
sers, sulphur,  hyalite,  cinnabar;  Lower  Lake,  chromite. 

Los  ANGELES  Co. — Near  Santa  Anna  River,  anhydrite;  Williams 
Pass,  chalcedony;  Soledad  mines,  chalcopyrite.  garnet,  gypsum; 
Mountain  Meadows,  garnet,  in  copper  ore;  at  Brea  Branch,  vivianite 
nodules  with  asphaltum;  at  Compton,  Kelsey  mine,  erythrite. 

MARIPOSA  Co. — Chtilcopyrite,  itacolumyte;  Centreville,  cinnabar; 


CATALOGUE    OF   AMERICAN  LOCALITIES   OF   MINERALS.    397 

Pine  Tree  mine,  tetrahedrite;  Burns  Creek,  limonite;  Geyer  Gulch, 
pyrophyllite;  La  Victoria  mine,  azurite  !  near  Coulterville,  cinnabar, 
gold. 

MONO  Co.— At  Blind  Spring.  Partzite  (stibiconite),  cbalcocite, 
chalcopyrite,  tetrahedrite;  at  Bodie,  gold,  silver;  at  Iridian,  tetra- 
hedrite, sphalerite,  galenite,  silver. 

MONTEREY  Co.— ^Alisal  mine,  arsenic;  near  Paneches,  chalcedony; 
New  Idria  mine,  cinnabar ;  near  New  Idria,  chromite,  zaratite, 
chrome  garnet;  near  Pacheco's  Pass,  stibnite. 

NAPA  Co. — Chromite;  at  Cat  Hill,  Redington  mine,  cinnabar, 
metacinnabarite,  marcasite,  bitumen. 

NEVADA  Co.— Grass  Valley,  gold!  in  quartz  veins,  with  pyrite, 
rhalcopyrite,  blende,  arsenopyrite,  galenite,  quartz,  biotite;  near 
Truckee  Pass,  gypsum;  Excelsior  Mine,  molybdenite,  with  gold; 
Sweet  Land,  pyrolusite. 

PLACER  Co. — Miner's  Ravine,  epidote!  with  quartz,  gold. 

PLUMAS  Co. — At  Cherokee,  chalcopyrite. 

SANTA  BARBARA  Co.— San  Amedio  Canon,  stibnite.  asphaltum, 
bitumen,  maltha,  petroleum,  cinnabar,  iodide  of  mercury;  Santa 
Clara  River,  sulphur. 

SAN  BERNARDINO  Co. — Colorado  River,  agate,  trona;  at  Clarke 
and  Silver  Mountain,  stromeyerite,  malachite;  at  Tt-mescal  Mts., 
cassiterite;  Russ  District,  galenite,  cerussite;  Francis  mine,  cerar- 
gyrite;  Slate  Range,  thenardite,  borax,  common  salt,  hanksite;  San 
Bernardino  Mts.,  graphite. 

SANTA  CLARA  Co. — New  Almaden,  cinnabar,  mercury,  caldte, 
aragonite,  serpentine,  chrysolite,  quartz,  aragotite;  North  Almaden, 
chromite;  Mt.  Diabolo  Range,  magnesite,  datolite,  with  vesuvianite 
and  garnet. 

SAN  FRANCISCO  Co. — Red  Island,  pyrolusite  and  manganese  ores. 

SAN  Luis  OBISPO  Co. — Asphaltum,  cinnabar,  native  mercury, 
chromite. 

SIERRA  Co. — Forest  City,  gold,  arsenopyrite,  tellurides. 

SONOMA  Co. — At  Guerneville,  actinolite,  garnets,  chromite,  ser- 
pentine, cinnabar,  bitumen. 

TRINITY  Co. — At  Cinnabar,  cinnabar,  serpentine. 

TUOLDMNE  Co. — Tourmaline,  tremolite;  Sonora,  graphite,  gold, 
chalcopyrite,  pyrite;  York  Tent,  chromite;  Golden  Rule  mine, 
petzite,  calaverite,  altaite,  hessite,  magnesite,  tetrahedrite,  gold; 
Whiskey  Hill,  gold! 

LOWER  CALIFORNIA. 

LA  PAZ.  cuproscheelite.  LORETTO,  natrolite,  siderite,  selenite. 
VOLCANO  OP  CERRO  DE  LAS  VIRGINES,  leucite. 

OREGON. 

Gold  is  obtained  west  of  the  Cascade  Range,  in  the  southernmost 
counties,  Josephine,  Jackson,  and  Curry,  in  Coos  and  Douglass, 
the  next  north,  and  cast  of  the  range,  in  southeastern  Oregon,  in 
Grant  and  Baker  counties,  and  to  the  north  sparingly  in  Wasco, 


398  SUPPLEMENT  TO    DESCRIPTIONS   OF   SPECIES. 

Umatilla,  and  Union  counties.  The  most  productive  mines  are  in 
Baker  Co. 

BAKER  Co. — In  northern  part,  about  Baker  City,  Rye  Valley, 
Bridgeport  on  Burnt  River,  Willow  Creek,  Silver  Creek,  gold;  Rye 
Valley  and  Silver  Creek  affording  also  stromeyerite,  arsenopyrite, 
pyrite,  malachite,  azurite. 

CURRY  Co. — Near  Port  Orford  and  Cape  Blanco,  and  on  the 
Rogue  River,  gold,  platinum,  iridosmine,  laurite.  On  the  seashore, 
5  m.  N.  of  Chetko,  priceite,  in  veins  and  in  masses  from  20  Ibs. 
•weight  to  the  size  of  peas  and  smaller,  with  bluish  steatite. 

DOUGLASS  Co. — New  Idrian,  cinnabar,  limonite;  in  PineyMtn., 
hydrous  nickel  silicate. 

GRANT  Co. — Granite,  in  north  part  of  county,  tetrahedrite,  poty- 
basite,  chalcopyrite,  pyrite,  sphalerite.  At  Elk  Creek,  auriferous 
gravel;  near  Canyon  City  (on  John  Day's  II.)  cinnabar. 

JACKSON  Co. — At  Applegate  and  elsewhere,  auriferous  gravel. 

JOSEPHINE  Co. — Auriferous  gravel ;  at  Yank,  galenite,  chalcopy- 
rite. 

WASCO  Co. — At  Ochoco,  auriferous  gravel. 

WASHINGTON. 

KING  "Co. — Seattle,  scheelite,  tourmaline;  magnetite  at  Iron 
Mt.,  3  m.  N.  W.  of  Snoqualmie  Pass,  and  also  copper  ores  at  the 
Denny  Co.  mine. 

STEVENS  Co. — Colville  district  mines  of  lead  and  silver  reported. 

WHATCOM  Co. — Fidalgo,  tourmaline. 

YAKIMA  Co.— Auriferous  gravel  and  quartz  veins. 


DOMINION    OF   CANADA. 
PROVINCE  OF  QUEBEC. 

ABERCROMB  IE. — Labradorite. 

ALDFIELD,  Pontiac  Co. — Molybdenite!  ! 

ALLEYN  TOWNSHIP.  Pontiac  Co.— Molybdenite,  molybdite. 

AUBERT.— Gold,  iridosmine,  platinum. 

BAIE  ST.  PAUL. — Menaccanite !  apatite,  allanite,  rutile. 

BOLTON. — Cfiromite,  magnesile,  serpentine,  picrolite,  steatite,  bitter 
epnr,  wad,  rutile. 

BOUCIIERVILLE. — Augite  in  trap. 

BRASSARD,  Bertbier  Co.— Samarskite. 

BROME. — Magnetite,  chalcopyrite,  sphene,  menaccanite,  phyllite, 
soda  lite,  cancrinite,  galenite,  chloritoid,  rutile. 

BROUGHTON. — Serpentine,  chrysotile,  steatite. 

BUCKINGHAM  TOWNSHIP,  Ottawa  County. — Apatite  and  various 
associated  minerals. 

CIIAMBLY. — Analcite,  chabazite  and  calcite  in  trachyte,  menac- 
canite. 

CHATEAU  RICHER. — Labrador ite,  hypersthene,  andesite. 

DAILLEBOUT. — Blue  spinel  with  clintonite. 


CATALOGUE   OF  AMERICAN   LOCALITIES   OF  MINERALS.    399 

GRENVILLE. — Wollastonite,  sphene,  muscomte,  vesuvianite,  cal- 
cite, pyroxene,  serpentine,  steatite  (rensselaerite),  choudrodite,  garnet 
(cinnamon-stone),  zircon,  graphite,  scapolite. 

FITZROY. — Graphite. 

HAM. — Chromite  in  serpentine,  diallage,  antimony  !  senarmontite  ! 
kermesite  f  valentinite,  stibnite. 

HULL  TOWNSHIP,  Ottawa  County. — Apatite,  hornblende,  titanite, 
tourmaline,  barite,  fluorite,  jasper  (Chelsea). 

HUNTERSTOWN. — Scapolite,  sphene,  vesuvianite,  garnet,  brown  tour- 
maline f 

INVERNESS. — Bornite,  chalcocite,  pyrite. 

JONQUIERE  TOWNSHIP. — Beryl. 

LAKE  ST.  FRANCIS. — Andalusite  in  mica  schist. 

LEEDS. — Dolomite,  chalcopyrite,  gold,  chloritoid,  chalcocite,  bor- 
nite,  pyrite,  steatite. 

MAISONNEUVE  TOWNSHIP,  Berthier  County. — Samarskite,  beryl, 
muscovite. 

MILLE  ISLES. — Labradorite  !  menaccanite,  hypersthene,  andesite, 
zircon. 

MONTREAL. — Calcite,  augite,  sphene  in  trap,  chrysolite,  natrolite, 
dawsonite,  sodalite,  acmite. 

MORIN. — SpJiene,  apatite,  Idbradorite. 

MOUNT  ALBERT.— Chrysolite. 

ORFORD. — White  garnet,  chrome  garnet,  mitterite,  serpentine, 
pyroxene. 

PORTAGE  DU  FORT. — Rensselaerite. 

POTTON. — Chromite,  steatite,  serpentine,  amianthus. 

ROUGEMONT. — Augite  in  trap. 

ST.  ARMAND. — Micaceous  iron  ore  with  quartz,  epidote. 

ST.  FRANCOIS  BEAUCE. — Gold,  platinum,  iridosmine,  menaccan- 
ite, magnetite,  serpentine,  chromite,  soapstoue,  barite. 

ST.  JEROME. — Sphene,  apatite,  chondrodite,  phlogopite,  tourmaline, 
zircon,  garnet,  molybdenite,  pyrrhotite,  wollastonite,  labradorite. 

ST.  NORBERT. — Amethyst  in  greenstone. 

SHERBROOKE. — At  Suffield  mine,  albite !  native  silver,  argentite, 
chalcopyrite,  blende. 

STUKELEY. — Serpentine,  verd-antique  !  schiller  spar. 

SUTTON. — Magnetite  in  fine  crystals,  hematite,  rutile,  dolomite, 
magnesite,  chromiferous  talc,  bitter  spar,  steatite. 

TEMPLETON  TOWNSHIP,  Ottawa  County. — Apatite!  rutile,  titan- 
ite, scapolite,  tourmaline  (blk.),  hematite  (Haycock  mine),  wollaston- 
ite, pyroxene,  zircon,  vemvianite  !  phlogopite!  chrysotile,  hornblende, 
prehnite,  wilsonite,  chabazite,  stilbite,  uralite. 

THETFORD  . — Chrysotile  ! 

UPTON.— dhalcopy rite,  malachite,  calcite. 

VAUDREUIL. — Limonite,  vivianite. 

WAKEFIELD  TOWNSHIP,  Ottawa  County.  —  Apatite!  titanite, 
pyroxene,  garnet,  zircon,  vesuvianite,  scapolite,  phlogopite,  calcite 
(blue),  spinel,  tourmaline  (blk). 

YAMASKA. — Sphene  in  trap. 


400  SUPPLEMENT  TO   DESCRIPTIONS  OF  SPECIES. 

PROVINCE  OF  ONTARIO. 

ARNFRTOR. — Calcite. 

BALSAM  LAKE. — Molybdenite,  scapolite,  quartz,  pyroxene,  pyrite. 

BATHURST. — Barite,  black  tourmaline,  perthite  (orthoclase),  perister- 
ite  (albite),  bytownite,  pyroxene,  wilsonite,  scapolite,  apatite,  titanite, 

BRANTFORD. — Sulphuric  acid  spring  (4*2  parts  of  pure  sulphuric 
acid  in  1,000). 

B  ROCKVILLE  .  — Pyrite. 

BRUCE  MINES  on  Lake  Huron. — Calcite,  dolomite,  quartz,  chalco- 
pyrite, chalcocite. 

BURGESS. — Pyroxene,  albite,  mica,  corundum,  sphene,  chalcopyrite, 
apatite,  black  spinel !  spodumene  (in  a  bowlder),  serpentine,  biotite. 

CALABOGIE  LAKE. — Tremolite. 

CAPE  IPPERWASH,  Lake  Huron. — Oxalite  in  shales. 

CLARENDON. —  Vesuvianite,  tourmaline. 

CREDIT  RIVER  (forks  of  the). — Red  celestite. 

DALHOUSIE. — Hornblende,  dolomite. 

DELORO. — Arsenopyrite  !  gold,  calcite,  chalcodite. 

DRUMMOND. — Labradorite. 

ELIZABETH-TOWN. — Pyrrhotite,  pyrite,  calcite,  magnetite,  talc,  phlo- 
gopite,  siderite,  apatite,  cacoxenite. 

ELMSLEY. — Pyroxene,  spheue,  feldspar,  tourmaline,  apatite,  biotite, 
zircon,  red  spinel,  chondrodite. 

FITZROY.— Amber,  brown  tourmaline  in  quartz. 

GRAND  CALUMET  ISLAND. — Apatite,  phlogopite!  pyroxene!  horn- 
blende, sphene,  vesuvia?i<te !  serpentine,  treinolite,  scapolite,  brown 
and  black  tourmaline!  pyrite,  loganite. 

HIGH  FALLS  OF  THE  MADAWASKA. — Pyroxene!  hornblende. 

INNISKILLEN. — Petroleum. 

JACKFISH  LAKE,  Huronian  Mine. — Sylvanite. 

KINGSTON. — Celestite. 

LAC  DES  CHATS,  Island  Portage. — Brown  tourmaline  !  pyrite,  cal- 
cite, quartz. 

LANARK. — Raphilite  (hornblende),  serpentine,  asbestus,  perthite 
(aventurine  feldspar),  peristerite. 

LANSDOWNE. — Celestite,  vein  27  in.  wide,  and  fine  crystals,  rens- 
seinerite,  sphalerite,  wiisonite,  labradorite. 

LITTLE  RIDEAU.— Celestite  (fibrous). 

MADOC. — Magnetite. 

MARBLE  LAKE,  Barrie  Township. — Meneghinite,  galena. 

MARMORA. — Magnetite,  chalcolite,  serpentine,  garnet,  epsomite, 
hematite,  steatite,  arsenopyrite,  gold. 

McN^B. — Hematite,  barite. 

MICHIPICOTEN  ISLAND,  Lake  Superior. — Domeykite,  niccolite,  gen- 
thite,  chalcopyrite,  native  copper,  native  silver,  chalcocite,  galenite, 
amethyst,  calcite,  stilbite,  analcite;  at  Maimanse  Bay,  Coracite,  chal- 
cocite, chalcopyrite,  native  copper. 

NEWBOROUGH. — Chondrodite,  graphite. 

PAKENHAM.  —Hornblende. 

PERTH. — Apatite  in  large  beds,  phlogopite. 

Ross  TOWNSHIP,  Renfrew  County. — Apatite,  titanite,  hornblende, 
pyroxene,  orthoclase,  scapolite,  chrysotile,  molybdenite,  molybdite. 


CATALOGUE   OF   AMERICAN   LOCALITIES   OF  MINERALS.    401 

ST.  ADELE. — Chondrodite  in  limestone. 

ST.  IGNACE  ISLAND. — Calcite,  native  copper. 

SEBASTOPOL  Township,  Renfrew  County. — Apatite!  titanite!  zir- 
con. !  hornblende,  ortJioclase,  microcline,  scapolite,  pyroxene,  calcite. 

SILVER  ISLET,  Lake  Superior. — Argentite,  native  silver,  galenite, 
niccolite,  clialcocite,  malachite. 

SOUTH  CROSBY.— Chondrodite. 

SYDENHAM. — Celestite. 

TERRACE  COVE,  Lake  Superior. — Molybdenite. 

VERONA  (near).— Black  tourmaline. 

WALLACE  MINE,  Lake  Huron.— Hematite,  nickel  ore,  nickel  vitriol, 
chalcopyritt. 

PROVINCE  OF  NEW  BRUNSWICK. 

ALBERT  Co. — Hopewell  on  Shepody  Bay,  gypsum,  manganese 
ores ;  Albert  mines,  near  Hillsboro',  nlbertite  (largely  exported) ; 
Shepody  Mountain,  alunite  in  clay,  calcite,  pyrite,  manyanite,  psilo- 
melane,  pyrolusite,  gypsum  (quarried),  anhydrite  (with  the  gypsum). 

CARLETON  Co. — Woodstock,  chalcopyrite,  hematite,  limonite,  wad. 

CHARLOTTE  Co. — Campobello,  at  Welchpool,  blende,  chalcopyrite, 
bornite,  galenite,  pyrite;  at  head  of  Harbor  de  Lute,  galenite;  Deer 
Island,  on  west  side,  calcite,  magnetite,  quartz  crystals;  Digdighash 
River  on  west  side  of  entrance,  calcite!  (in  conglomerate),  chalcedony; 
at  Rolling  Dam,  graphite;  Grand  Manan,  between  Northern  Head 
and  Dark  Harbor,  agate,  amethyst,  apophyllite,  cnlcife,  hematite,  heu- 
landite,  jasper,  magnetite,  natrolite,  stilbite;  at  Whale  Cove,  calcite  ! 
heulandite,  laumontite,  stilbite;  semi-opal !  ;  Wagaguadavic  River,  at 
entrance,  azurite,  chalcopyrite,  in  veins,  malachite. 

GLOUCESTER  Co. — Tete-a-Gouche  River,  eight  miles  from  Bathurst, 
chalcopyrite  (mined),  oxide  of  manganese!  formerly  mined. 

KINGS  Co. — Sussex,  near  Cloat's  mills,  on  road  to  Belle  Isle,  ar- 
gentiferous galenite  ;  one  mile  north  of  Baxter's  Inn,  liematite  in 
crystals,  limonite;  on  Capt.  McCready's  farm,  selenite! ;  at  Upham, 
manganese  ores,  gypsum. 

RESTIGOUCHE  Co. — Belledune  Point,  calcite!  serpentine,  verd-an- 
tique  ;  Dalhousie.  agate,  carnelian. 

ST.  JOHN  Co. — Black  River,  on  coast,  calcite,  chlorite,  chalcopyrite, 
hematite!  Brandy  Brook,  epidote,  hornblende,  quartz  crystals;  Carle- 
ton,  near  Falls,  calcite;  Chance  Harbor,  calcite  in  quartz  veins,  chlo- 
rite in  argillaceous  and  talcose  slate;  Little  Dipper  Harbor,  on  west 
side,  in  greenstone,  amethyst,  barite,  quartz  crystals ;  Moosepath, 
feldspar,  hornblende,  muscovite,  black  tourmaline ;  Musquash,  on 
east  side  harbor,  copperas,  graphite,  p}rrite;  at  Shannon's,  chrysolite, 
serpentine;  east  side  of  Musquash,  quartz  crystals!  ;  Portland  at  the 
Falls,  graphite;  at  Fort  Howe  Hill,  calcite,  graphite ;  Crow's  Nest, 
asbestus,  chrysolite,  magnetite,  serpentine,  steatite;  Lily  Lake,  white 
augite  ?  chrysolite,  graphite,  serpentine,  steatite  talc;  How's  Road, 
two  miles  out,  epidote  (in  syenyte),  steatite  in  limestone,  tremolite ; 
Drury's  Cove,  graphite,  pyrite,  pyrallolite?  indurated  talc;  Quaco,  at 
Lighthouse  Point,  large  bed  oxide  of  manganese;  Sheldon's  Point, 
actinolite,  asbestus,  calcite,  epidote,  malachite,  specular  iron ;  Cape 


402  SUPPLEMENT  TO   DESCRIPTIONS  OF  SPECIES. 

Spenser,  asbestus,  calcite,  chlorite,  specular  iron  (in  crystals);  West- 
beach,  at  east  end  on  Evans's  Farm,  chlorite,  talc,  quartz  crystals; 
half  a  mile  west,  chlorite,  chalcopyrite,  magnesite  (vein),  magnetite  ; 
Point  Wolf  and  Salmon  River,  asbestus,  chlorite,  chrysocolla,  chalco- 
pyrite, bornite,  pyrite. 

VICTORIA  Co.— Tabique  Eiver,  etc/ate,  carnelian,  jasper  ;  at  mouth, 
south  side,  galenite;  at  mouth  of  Wapskanegan,  gypsum,  salt  spring; 
three  miles  above,  stalactites  (abundant);  Quisabis  River,  blue  phos- 
phate of  iron,  in  clay. 

WESTMORELAND  Co. — Bellevue,  pyrite ;  Dorchester,  on  Taylor's 
Farm,  cannel  coal;  clay  ironstone;  on  Ayer's  Farm,  asphaltum,  petro- 
leum spring;  Grandlance,  apatite,  selenite  (in  large  crystals);  Mem- 
ramcook,  coal  (albertite);  Shediac,  four  miles  up  Scadoue  River,  coal. 

YORK  Co. — Near  Fredericton,  Prince  William  mine,  slibnite 
(mined),  native  antimony,  jamesonite,  berthierite ;  Pokiock  River, 
stibnite,  tin  pyrites  ?  in  granite  (rare). 

PROVINCE  OF  NOVA  SCOTIA. 

ANNAPOLIS  Co. — Chute's  Cove,  apophyllite,  natrolite;  Gates's  Moun- 
tain, analcite,  magnetite,  mesolite  !  natrolite,  stilbite;  Martial's  Cove, 
analcite!  chabazite,  heulandite;  Moose  River,  beds  of  magnetite; 
Nictau  River,  at  the  Falls,  bed  of  hematite;  Paradise  River,  black 
tourmaline,  smoky  quartz! ;  Port  George,  faroelite,  laumontite,  me- 
solite, stilbite;  east  of  Port  George,  on  coast,  apophyllite  containing 
gyrolite  ;  Peter's  Point,  west  side  of  Stonock's  Brook,  apophyllile~! 
calcite,  heulandite,  Icmmontite!  (abundant),  native  copper,  stilbite; 
St.  Croix's  Cove,  chabazite,  heulandite. 

ANTAGONISH  Co. — College  Lake,  cJialcopyrite ;  on  St.  George's 
Bay,  and  elsewhere,  gypsum,  in  thick  strata. 

CAPE  BRETON  Co. — At  Gabarus,  molybdenite,  bismuth  glance;  at 
Loch  Lomond,  Salmon  River,  manganese  ore;  at  Plaister  Cove, 
Mabou,  Port  Hood,  etc.,  gypsum  ;  near  Sydney,  copper  ores. 

COLCHESTER  Co. — Five  Islands,  East  River,  barite,  calcite,  dolo- 
mite (ankerite),  hematite,  chalcopyrite ;  Indian  Point,  malachite, 
magnetite,  red  copper,  tetrahedrite;  Pinnacle  Islands,  ana1  cite,  calcite, 
chabazite!  natrolite,  siliceous  sinter;  Londonderry,  on  branch  of  Great 
Village  River,  barite  !  ankerite,  hematite,  limonite,  magnetite ;  Cook's 
Brook,  ankerite,  hematite  ;  Martin's  Brook,  hematite,  limonite  ;  at 
Folly  River,  below  Falls,  ankerite,  pyrite;  on  high  land,  east  of  river, 
ankerite,  hematite,  limonite  ;  on  Archibald's  land,  ankerite,  barite, 
hematite  ;  Salmon  River,  south  branch  of,  chalcopyrite,  hematite  ; 
Shubenacadie  River,  anhydrite,  calcite,  barite,  hematite,  oxide  of 
manganese ;  at  the  Canal,  pyrite  ;  Stewiacke  River,  barite  (in  lime- 
stone; 800  tons  mined  in  1885) ;  at  Onslow,  manganese  ore. 

CUMBERLAND  Co. — Cape  Chiegnecto,  barite ;  Cape  d'Or,  analcite, 
apophyllite!  chabazite,  faroelite,  laumontite,  mesolite,  malachite, 
natrolite,  native  copper,  obsidian,  red  copper  (rare),  vivianite  (rare)  ; 
Horse  Shoe  Cove,  east  side  of  Cape  d'Or,  analcite,  calcite,  stilbite , 
Isle  Haute,  south  side,  analcite,  apophyllite!  calcite,  heulandite! 
natrolite,  mesolite,  stilbite! ;  Joggins,  coal,  hematite,  limonite;  mala- 
chite and  tetrahedrite  at  Seaman's  Brook  ;  Partridge  Island,  analcite, 


CATALOGUE  OF  AMERICAN  LOCALITIES  OF  MINERALS.    403 

apophyllite !  (rare),  amethyst !  agate,  apatite  (rare),  calcite !  chabazite 
(acadialite),  chalcedony,  cat's- eye  (rare),  gypsum,  hematite,  heulan- 
dite!  magnetite,  stilbite-!  ;  Swan's  Creek,  west  side,  near  the  Point, 
calcite,  gypsum,  heulandite,  pyrite  ;  east  side,  at  Wesson's  Bluff  and 
vicinity,  analcite!  apophyllite!  (rare),  calcite,  chabazite!  (acadinlitc), 
gypsum,  heulandite  !  natrolite  !  siliceous  sinter  ;  Two  Islands,  moss 
agate,  analcite,  calcite,  chabazite,  heulandite ;  McKay's  Head,  anal- 
cite, calcite,  heulandite,  siliceous  sinter  !  ;  at  Amherst,  manganese  ore. 

DIGBY  Co. — Briar  Island,  native  copper,  in  trap  ;  Digby  Neck, 
Sandy  Cove  and  vicinity,  agate,  amethyst,  calcite,  chabazite,  hematite  ! 
laumontite  (abundant),  magnetite,  stilbite,  quartz  crystals  ;  Gulliver's 
Hole,  magnetite,  stilbite! ;  Mink  Cove,  amethyst,  chabazite!  quartz 
crystals ;  Nichols  Mountain,  south  side,  amethyst,  magnetite  !  ;  Wil- 
liams Brook,  near  source,  cJiabazite  (green),  heulandite,  stilbite,  quartz 
crystal. 

GUYSBORO'  Co.— Cape  Canseau,  andalusite. 

HALIFAX  Co. — Gay's  River,  galenite  in  limestone ;  southwest  of 
Halifax,  garnet,  staurolite,  tourmaline;  Tangier,  gold!  in  quartz  veins 
in  clay  slate,  associated  with  auriferous  pyrite,  galenite,  hematite, 
arsenopyrite,  and  magnetite;  gold  at  Country  Harbor,  Fort  Clarence, 
Isaac's  Harbor,  Indian  Harbor,  Laidlow's  Farm,  Lawrencetown,  Sher- 
brooke,  Salmon  River,  Wine  Cove,  and  other  places ;  at  Hammond's 
Plains  and  Musquodobpit,  molybdenite. 

HANTS  Co. — Cheverie,  oxide  of  manganese  (in  limestone),  gypsum; 
Petite  River,  gypsum,  oxide  of  manganese  ;  Walton,  pyroiusite,  man- 
ganite  ;  Teny  Cape,  manganese  ores;  Windsor,  calcite,  gypsum  (great 
bed),  with  cryptomorphite  (baronatrocalcite),  howlite,  glauber  salt ; 
at  Rawdon,  stibnite,  of  which  758  tons  (valued  at  $33,095)  were  ex- 
ported in  1885  ;  at  Teny  Cape,  manganese  ore. 

KINGS  Co.— Black  Rock,  central  lassite,  cerinite,  cyanolite ;  a  few 
miles  east  of  Black  Rock,  prehnite?  siilbite  !  ;  Cape  Blcmidon,  on  the 
coast  between  the  cape  and  Cape  Split,  the  following  minerals  occur 
in  many  places  (some  of  the  best  localities  are  nearly  opposite  Cape 
Sharp) :  analcite  !  agate,  amethyst !  apophyltite  !  calcite,  chalcedony, 
chabazite,  gmelinite  (lederite),  hematite,  heulandiie!  laumontite,  mag- 
netite, maiachitc^mesolite,  native  copper  (rare),  natrolite  !  psilomelane, 
stilbite !  thomsonite,  faroclite,  quartz ;  North  Mountains,  amethyst, 
bloodstone  (rare),  ferruginous  quartz,  mesolite  (in  soil) ;  Long  Point, 
five  miles  west  of  Black  Rock,  Jieulandite,  laumontite !  stilbite ! ; 
Morden,  apophyllite,  mordenite ;  Scott's  Bay,  agate,  amethyst,  chalce- 
dony, mesolite,  natrolite;  Woodworth's  Cove,  a  few  miles  west  of 
Scott's  Bay,  agate  !  chalcedony  !  jasper. 

LUNENBURG  Co.— Chester,  Gold  River,  gold  in  quartz,  pyrite,  mis- 
pickel ;  Cape  la  Have,  pyrite ;  The  "  Ovens,"  gold,  pyrite,  arseno- 
pyrite ;  Petite  River,  gold  in  slate. 

PICTOU  Co. — Pictou,  jet,  oxide  of  manganese,  limonite  ;  at  Roder's 
Hill,  six  miles  west  of  Pictou,  barite  ;  on  Caribou  River,  gray  copper 
and  malachite  in  lignite  ;  at  Albion  mines,  coal,  limonite;  East  River, 
limonite,  hematite,  magnetite,  siderite,  ankcrite;  on  Sutherland's  R., 
siderite ;  at  Smithfield,  argentiferous  galenite. 

QUEEN'S  Co. — Westfield,  gold  in  quartz,  pyrite,  arsenopyrite;  Five 
Rivers,  near  Big  Fall,  gold  in  quartz,  pyrite,  arsenopyrite,  limonite. 


404  SUPPLEMENT  TO   DESCRIPTIONS  OF  SPECIES. 

RICHMOND  Co. — West  of  Plaister  Cove,  barite  and  calcite  in  sand- 
stone ;  nearer  the  Cove,  calcite,  fluorite  (blue),  siclerite;  gypsum  in  beds 
of  great  tbickness  (giving  tbe  name  to  Plaister  Cove). 

SHELBURNE  Co. — Sbelburne,  near  mouth  of  harbor,  garnets  (in 
gneiss) ;  near  tbe  town,  rose  quartz  ;  at  Jordan  and  Sable  River,  stau- 
rolite  (abundant),  scbiller  spar. 

SYDNEY  Co. — Hills  east  of  Locbaber  Lake,  pyrite,  chalcopyrite,  side- 
rite,  bematite;  Morristown,  epidote  in  trap,  gypsum  (making  a  cliif  of 
200  feet,  near  Ogden's  Lake). 

YARMOUTH  Co.— Cream  Pot,  above  Cranberry  Hill,  gold  in  quartz, 
pyrite  ;  Cat  Rock,  Fourcbu  Point,  asbestus,  calcite. 


PROVINCE  OF  BRITISH  COLUMBIA. 

CARIBOO  DISTRICT. — Native  gold,  galena. 

ON  FRAZER  RIVER. — Gold,  argentiferous  tetrabedrite,  cerargyrite, 
cinnabar. 

OMINICA  DISTRICT. — Native  gold,  argentiferous  galenite,  native 
silver,  silver-amalgam. 

HOWE'S  SOUND. — Bornite,  molybdenite,  mica. 

TEXADA  ID. — Magnetite. 

SHUSWAP  LAKE. — Bismuthinite. 


NEWFOUNDLAND. 

ANTONY'S  ISLAND. — Pyrite. 

CATALINA  HARBOR. — On  the  shore,  pyrite  ! 

CHALKY  HILL. — Feldspar. 

COPPER  ISLAND,  one  of  tbe  Wadbam  group. — Chalcopyrite. 

CONCEPTION  BAY.— On  the  shore  south  of  Brigus,  bornite  and  gray 
copper  in  trap. 

BAY  OF  ISLANDS. — Southern  shore,  pyrite  in  slate. 

LAWN. — Galenite,  cerargyrite,  proustite,  argentite. 

PLACENTIA  BAY. — At  La  Manche,  two  miles  eastward  of  Little 
Southern  Harbor,  galenite! ;  on  the  opposite  side  of  the  isthmus  from 
Placentia  Bay,  barite  in  a  large  vein,  occasionally  accompanied  by 
chalcopyrite. 

SHOAL  BAY. — South  of  St.  John's,  chalcopyrite. 

TRINITY  BAY. — Western  extremity,  barite. 

HARBOR  GREAT  ST.  LAWRENCE.— West  side,  fluorite.  galenite. 


DETERMINATION  OF  MINERALS.  405 


V.  DETERIMNATION  OF  MINERALS- 

IN"  the  determination  of  minerals,  no  one  order  in  the  suc- 
cession in  which  characters  should  be  examined  answers  for 
all  minerals,,  or  even  for  all  of  the  same  section  of  species. 

The  points  to  be  first  examined  are:  Hardness,  which 
may  be  tried  by  the  point  of  a  knife-blade,  if  a  file  or  scale 
of  hardness  is  not  at  hand;  and  fusibility  before  the  blow- 
pipe, with  other  blowpipe  reactions;  and,  in  the  case  of 
species  of  unmetallic  lustre,  solubility  or  not  in  hydrochloric 
acid  (HC1),  the  dilute  acid  serving  to  test  effervescence 
from  the  escape  of  carbonic  acid  (carbon  dioxide,  C02),  and 
the  strong  acid,  to  ascertain  whether  the  mineral  gelatinizes 
or  not,  and  other  points  already  explained. 

For  species  having  a  metallic  lustre,  the  order  of  easiest 
application  is  generally,  after  trials  of  hardness,  fusibility, 
and  blowpipe  reactions:  Color;  sectility,  which  distin- 
guishes argentite,  amalgarn,  and  some  native  metals  from 
other  species  of  metallic  lustre;  streaky  whether  metallic 
or  not,  and  the  color  of  the  powder  or  rubbed  surface; 
specific  gravity,  care  being  taken  thai^  the  specimen  is  pure; 
action  of  nitric  acid;  crystalline  form  and  cleavage,  a  char- 
acter of  the  highest  importance;  optical  characters,  in  spe- 
cies that  transmit  light  when  in  thin  slices. 

For  species  without  metallic  lustre,  after  trial  of  hard- 
ness, B.B.  characters,  and  solubility  in  acid:  Color,  but 
with  doubt  of  its  value,  as  impurities  often  cause  great 
variations;  streak,  when  it  is  decidedly  colored;  specific 
gravity ;  sectilify,  when  perfect  like  that  of  wax,  which 
distinguishes  cerargyrite  and  a  related  species;  crystalline 
form  and  cleavage;  taste,  in  the  case  of  soluble  species; 
optical  characters,  which  are  always  important,  and  may  be 
the  best  available  means. 

The  following  hints  may  be  of  service  to  the  beginner  in 
the  science,  by  enabling  him  to  overcome  a  difficulty  in  the 
outset,  arising  from  the  various  forms  and  appearance  of  the 
minerals  quartz  and  limestone.  Quartz  occurs  of  nearly 
every  color,  and  of  various  degrees  of  glassy  lustre  to  a  dull 
stone  without  the  slightest  glistening.  The  common  gray- 
ish cobble-stones  of  the  fields  are  usually  quartz,  and  others 


406  DETERMINATION   OF   MINERALS. 

are  dull  red  and  brown;  from  these  there  are  gradual  transi- 
tions to  the  pellucid  quartz  crystal  that  looks  like  the  best 
of  glass.  Sandstones  are  often  wholly  quartz,  and  the  sea- 
shore sands  are  mostly  of  the  same  material.  It  is  therefore 
probable  that  this  mineral  will  be  often  encountered  in 
mineralogical  rambles. 

Let  the  first  trial  of  specimens  obtained  be  made  with  a 
file,  or  the  point  of  a  knife,  or  some  other  means  of  trying 
the  hardness;  if  the  file  makes  no  impression,  there  is  rea- 
son to  suspect  the  mineral  to  be  quartz;  and  if  on  breaking 
it,  no  regular  structure  or  cleavage  plane  is  observed,  but  it 
breaks  in  all  directions  with  a  similar  surface  and  a  more  or 
less  vitreous  lustre,  the  probability  is  much  strengthened 
that  this  conclusion  is  correct.  The  blowpipe  may'next  be 
used;  and  if  there  is  no  fusion  produced  by  it  in  a  careful 
trial  there  can  be  little  doubt  that  the  specimen  is  in  fact 
quartz. 

Calcite  (calcium  carbonate),  including  limestone,  is 
another  very  common  species.  If  the  mineral  collected  is 
rather  easily  impressible  with  a  file,  it  may  be  of  this  spe- 
cies; if  it  eifervesces  freely  when  placed  in  a  test-tube  con- 
taining dilute  hydrochloric  acid,  and  is  finally  dissolved,  the 
probability  of  its  being  carbonate  of  lime  is  increased;  if 
the  blowpipe  produces  no  trace  of  fusion,  but  a  brilliant 
light  from  the  fragment  before  it,  but  little  doubt  remains 
on  this  point.  Crystalline  fragments  of  calcite  break  with 
three  equal  oblique  cleavages. 

Familiarized  with  these  two  Protean  minerals  by  the 
above  and  other  trials,  the  student  has  already  surmounted 
the  principal  difficulties  in  the  way  of  future  progress. 
Frequently  the  young  beginner  who  has  devoted  some 
time  to  collecting  the  differently  colored  stones  in  his 
neighborhood,  on  presenting  them  for  names  to  some  prac- 
tised mineralogist,  is  a  little  disappointed  to  learn  that, 
with  two  or  three  exceptions,  his  large  variety  includes 
nothing  but  limestone  and  quartz.  He  is  perhaps  gratified, 
however,  at  being  told  that  he  may  call  this  specimen  yel- 
low jasper,  that  red  jasper,  another  flint,  and  another  horn- 
stone,  others  chert,  granular  quartz,  ferruginous  quartz, 
chalcedony,  prase,  smoky  quartz,  greasy  quartz,  milky 
quartz,  agate,  plasma,  hyaline  quartz,  quartz  crystal,  basa- 
nite,  radiated  quartz,  tabular  quartz,  etc.,  etc.;  and  it  is 
often  the  case,  in  this  state  of  his  knowledge,  that  he  is 


DETERMINATION   OF  MINERALS.  407 

best  pleased  with  some  treatise  on  the  science  in  which  all 
these  various  stones  are  treated  with  as  much  prominence 
as  if  actually  distinct  species;  being  loath  to  receive  the  un- 
welcome truth,  that  his  whole  extensive  cabinet  contains 
only  one  mineral.  But  the  mineralogical  stu dent  has  already 
made  good  progress  when  this  truth  is  freely  admitted,  and 
quartz  and  limestone,  in  all  their  varieties,  have  become 
known  to  him. 

The  student  should  be  familiar  with  the  use  of  the  blow- 
pipe and  the  reactions,  as  explained  on  pages  93  to  102; 
it  would  be  still  better  if  a  fuller  treatise  on  the  subject 
had  been  carefully  studied.  He  should  be  supplied  with  the 
three  acids  in  glass- stoppered  bottles;  a  fourth  bottle  con- 
taining hydrochloric  acid  diluted  one  half  with  water,  for 
obtaining  effervescence  with  carbonates;  test-tubes;  and 
also  the  ordinary  blowpipe  apparatus  and  tests,  including 
platinum  wire,  platinum  forceps,  glass  tube,  "  cobalt  solu- 
tion," litmus  and  turmeric  paper,  etc. 

Also  the  following: 

A  small  file,  three-cornered  or  flat,  for  testing  hardness. 

A  knife  with  a  pointed  blade  of  good  steel,  for  trying 
hardness.  It  may  be  magnetized,  to  be  used  as  a  magnet, 
though  a  good  horseshoe  magnet  of  small  size  is  better. 

The  series  of  crystallized  minerals,  constituting  the  scale 
of  hardness  (see  page  67).  Diamond  and  talc  are  least  es- 
sential. 

Cutting  pliers,  for  removing  chips  of  a  mineral  for  blow- 
pipe or  chemical  assay. 

A  pocket-lens. 

A  hammer  weighing  about  two  pounds,  resembling  a 
stone-cutter's  hammer,  having  a  flat  face,  and  at  the  oppo- 
site end  an  edge  having  the 
same  direction  as  the  handle. 
The  handle  should  be  made  of 
the  best  hickory,  and  the  mor- 
tise to  receive  it  should  be  as 
large  as  the  handle.  A  foot 

scale  should  be  marked  on  the  handle  of  the  hammer,  di- 
vided into  inches,  the  smallest  divisions  needed.  It  will  be 
often  of  use  in  getting  out  a  yard-stick,  or  a  ten-foot  pole, 
for  large  measurements.  A  similar  hammer,  having  the 
upper  part  prolonged  to  a  blunt  point,  to  be  used  like  a 
pick,  is  often  convenient. 


408         DETERMINATION  OF  MINERALS. 

A  hammer  of  half  a  pound  weight,  like  the  figure,  to  be 
used  in  trimming  specimens. 

A  small  jeweler's  hammer,  for  trying  the  malleability  of 
globules  obtained  by  the  blowpipe,  and  for  other  purposes, 
and  a  small  piece  of  steel  for  an  anvil. 

Two  steel  stone  chisels,  one  six  inches  long,  and  the  other 
three.  When  it  is  desired  to  pry  open  seams  in  rocks  with 
the  larger  chisel,  two  pieces  of  steel  plate  should  be  provided 
to  place  on  opposite  sides  of  "the  chisel,  after  ail  opening  is  ob- 
tained ;  this  protects  the  chisel  and  diminishes  friction  while 
driving  it. 

For  blasting,  if  this  is  desired : 

Three  hand-drills,  18,  24,  and  36  inches  long,  an  inch  in 
diameter.  The  best  form  is  a  square  bar  of  steel,  with  a 
diagonal  edge  at  one  end.  The  three  are  designed  to  fol- 
low one  another. 

A  sledge-hammer  of  six  or  eight  pounds  weight,  to  use  in 
driving  the  drill. 

A  sledge-hammer  of  ten  or  twelve  pounds  weight,  for 
breaking  up  the  blasted  rock. 

A  round  iron  spoon,  at  the  end  of  a  wire  fifteen  or  eigh- 
teen inches  long,  for  removing  the  pulverized  rock  from 
the  drill-hole. 

A  crowbar,  a  pickaxe,  and  a  hoe  for  removing  stones  and 
earth  before  or  after  blasting. 

Cartridges  of  blasting  powder,  to  use  in  wet  holes.  They 
should  one  third  fill  the  drill-hole.  After  the  charge  is  put 
in,  the  hole  should  be  filled  with  sand  and  gravel  alone 
without  ramming.  If  any  ramming  material  is  used,  plas- 
ter of  Paris  is  the  best,  which  has  been  wet  and  afterwards 
scraped  to  a  powder. 

Patent  fuse  for  slow  match,  to  be  inserted  in  the  car- 
tridge, and  to  lead  out  of  the  drill-hole. 

The  table  beyond  is  prepared  especially  to  aid  in  instruc- 
tion, and  comprises,  with  few  exceptions,  only  the  species 
that  are  described  in  large  type  through  the  work,  exclusive 
of  the  hydrocarbon  compounds.  Before  commencing  with 
the  table  in  the  determination  of  a  mineral,  it  is  best  to 
make  the  preliminary  trials  mentioned  on  page  405.  More- 
over, the  brief  description  of  a  species  should  be  supple- 
mented, whenever  a  doubt  arises,  by  turning  to  the  full 
description  in  the  earlier  part  of  the  book. 


DETERMINATION"  OF  MINERALS.          409 

The  following  abbreviations  are  used  in  the  table,  in  ad- 
dition to  those  explained  on  page  102.  With  reference  to 
colors:  bnh,  brownish;  bkh,  blackish;  grih,  greenish;  gyh, 
grayish;  rdh,  reddish.  The  acids:  nit.,  nitric  acid;  sulph. 
acid,  sulphuric  acid;  HCl.,  hydrochloric  acid;  sulph.,  sul- 
phur or  sulphurous  acid. 

Keactions:  gelatinizing  with  acid,  see  page  92;  reaction 
for  sulphur  ivith  soda,  see  page  101;  blue  or  red  color  with 
cobalt  solution,  see  page  98;  hydrou's,  jdelding  water  in  a 
closed  tube:  anhydrous,  not  yielding  water  in  a  closed  tube, 
or  only  traces,  see  page  98;  B.B.  lithium-red  color,  see  page 
98;  B.B.  green  flame  due  to  boron,  see  page  99;  coal  is  used 
for  charcoal;  fus.  for  fusible;  infus.  for  infusible;  sol.  for 
soluble;  st.  for  streak. 

In  using  the  blowpipe  it  is  important  to  remember  that 
a  trial  of  fusibility  with  the  forceps,  if  not  at  once  produc- 
ing fusion,  should  be  made  on  a  piece  of  the  mineral  not 
larger  than  the  fourth  of  an  ordinary  pin-head,  and  it  should 
be  either  oblong  and  slender,  or  thin,  and  be  made  to  pro- 
ject considerably  beyond  the  points  of  the  forceps,  lest  the 
forceps  carry  off  the  heat,  and  cause  a  failure  where  there 
ought  to  be  success.  Further,  it  should  be  in  mind,  that 
in  using  charcoal,  a  white  coating  is  always  a  consequence 
of  burning  it,  since  the  ash  from  its  own  combustion  is 
white.  Again,  before  testing  for  sulphur  by  means  of  soda 
and  a  polished  surface  of  silver,  it  is  necessary  to  try  the 
flame  and  the  soda  for  sulphur.  Gas-flame  always  con- 
tains traces  of  sulphur,  and  sometimes  too  much  for  safe 
conclusions  in  this  trial. 

A  mineralogist  sometimes  has  occasion  to  measure  dis- 
tances, and  by  the  following  method  he  may  make  himself 
quite  an  accurate  odometer: 

Let  him  first  find,  or  make,  along  a  roadside,  a  measured 
distance  of  800  to  1000  feet,  and  then  walk  it  at  his  ordi- 
nary walking  pace  three  or  four  times,  and  note  the  number 
of  steps.  He  will  thus  ascertain  the  actual  length  of  his 
pace,  and  also  find  that  in  his  ordinary  walk  it  does  not 
differ  much  from  thirty  inches;  it  may  be  an  inch  or  two 
less,  or  one,  two,  or  three  more  than  this.  Now  four  times 
thirty  inches  is  ten  feet.  If  then,  as  he  walks,  he  counts 
one  for  every  fourth  step,  each  unit  in  the  count  will  stand 
for  ten  feet  nearly,  and  100  for  1000  feet  nearly.  If  his 
pace  is  thirty-one  inches,  let  him  add  a  unit  for  every 


410  DETERMINATION   OF   MINERALS. 

thirty  in  the  counting,  or,  which  is  the  same  thing,  call  his 
thirty  thirty-one,  and  the  needed  correction  will  be  made; 
or  if  his  step  is  twenty- nine  and  one  half  inches,  subtract 
one  from  every  sixty  in  the  counting,  or  in  other  words  du- 
plicate the  sixtieth.  Or  the  correction  may  be  made  at  the 
end  of  the  pacing;  if  at  600,  this  number,  after  adding  a 
thirtieth,  becomes  620;  and  the  distance  would  hence  be 
6200  feet.  With  a  little  practice  the  counting  may  be 
carried  on  almost  unconsciously,  and  when  the  thoughts 
are  elsewhere;  that  is,  unless  there  is  a  talking  friend  by 
one's  side. 

An  instrument,  called  a  pedometer,  of  the  shape  and  size 
of  a  small  watch,  is  to  be  had  of  instrument-makers,  which, 
if  carried  in  the  waistcoat  pocket,  will  do  the  registering 
for  the  pedestrian  and  note  the  distance,  without  any  atten- 
tion on  his  part.  But  the  odometer  explained  above,  when 
once  in  working  order,  is  always  at  hand;  moreover,  the 
pocket  pedometer  measures  miles,  and  not  feet  or  yards. 


SYNOPSIS  OF  THE  ARRANGEMENT. 
I.  ELEMENTS. 

(None  of  the  species  in  the  other  subdivisions  have  the 
characters  here  enumerated:) 

1.  Lustre  metallic;  liquid. 

2.  Lustre  metallic;  malleable  and  eminently  sectile. 

3.  Lustre  metallic;  brittle;  B.B.  on  coal,  wholly  volatile,  with  no 

sulphurous  fumes. 

4.  Lustre  metallic;  brittle;  H.  —  1-2;  leaves  a  trace  on  paper;  B.B. 

on  coal,  infusible,  no  fumes  or  odor. 

5.  Unmetallic;  burns  readily  with  a  blue  flame. 

6.  Lustre  adamantine;  H.  =  10. 

II.  MINERALS  NOT  ELEMENTS   THAT   B.B.  ON 

COAL  ARE  WHOLLY  VOLATILE. 

1.  Lustre  metallic;  streak  metallic. 

2.  Lustre  unmetallic;  streak  same  as  color. 

III.  COMPOUNDS    OF    GOLD,    SILVER,    COPPER, 
LEAD,  TIN,  MERCURY,  CHROMIUM,  COBALT, 

MANGANESE:  yielding,  on  heating,  a  malleable,  or 


DETERMINATION   OF   MINERALS.  411 

liquid  (for  mercury  ores),  metallic  globule,  or  else 
affording  a  decisive  blowpipe  reaction  proving  the 
presence  of  one  or  more  of  these  metals. 

A.  Yielding  a  malleable  globule  B.B.  on  coal  with,  if  not 
without  soda. 

1.  Compounds  of  Gold. 

2.  Compounds  of  Silver. 

3.  Compounds  of  Copper. 

4.  Compounds  of  Lead. 

5.  Compounds  of  Tin. 

B.  Yielding  drops  of  mercury  when  heated  with  soda,  in 
a  closed  tube. 

1.  Compounds  of  Mercury. 

C.  A  decisive  reaction  with  borax  or  salt  of  phosphorus 
for  chromium,  cobalt,  or  manganese. 

1.  Compounds  of  Chromium.  . 

2.  Compounds  of  Cobalt. 

3.  Compounds  of  Manganese. 


IV.  MINERALS  OF  METALLIC  OE  SUBMETALLIC 
LUSTRE,  NOT  INCLUDED  IN  PRECEDING 
DIVISIONS. 

1.  Yielding  fumes  in  the  open  tube  or  on  coal,  but  not 
•Wholly  vaporizable. 

A.  Streak  metallic. 

B.  Streak  unmetallic. 

a.  Fumes  sulphurous  only. 

b.  Fumes  arsenical,  with  or  without  sulphurous. 

2.  Not  yielding  fumes  of  any  kind;  streak  unmetallic. 

A.  B.B.  easily  fusible,  giving  a  magnetic  bead;  lustre  sub- 

metallic. 

B.  Infusible,  or  nearly  so. 

a.  Reaction  for  iron;  anhydrous. 

b.  Reaction  for  iron;  hydrous. 

c.  Reaction  for  chromium  or  titanium. 

d.  Reaction  for  osmium  with  nitre. 


412         DETERMINATION"  OF  MINERALS. 

V.  MINERALS  OF  UNMETALLIC  LUSTKE. 

1.  Having  an  acid,  alkaline,  alum-like,  or  styptic  taste. 

A.  CARBONATES :  Taste  alkaline ;  effervescing  with  HOI. 

B.  SULPHATES:  No  effervescence;  reaction  for  sulphur 

with  soda. 

C.  NITRATES:  With  sulph.  acid,  reddish  acrid  fumes;  no 

action  with  HC1 ;  deflagrate. 

D.  CHLORIDES:  With  sulph.  acid,  acrid  fumes  of  HC1; 

no  fumes  with  HC1. 

E.  BORATES:  No  effervescence;  reaction  for  boron  when 

moistened  with  sulph.  acid. 

2.  Not  having  either  of  the  above-mentioned  kinds  of 
taste. 

A.  CARBONATES:  Effervescing  with  HC1. 

a.  Infusible;  assay  alkaline  after  ignition. 

b.  Infusible;  become  magnetic  acd  not  alkaline,  on 

ignition. 

c.  Infusible;   B.B.   on  coal  with  soda,   zinc  oxide 

vapors. 

d.  Infusible;  B.B.  on  coal  reaction  for  nickel. 

e.  Fusible;  assay  alkaline  after  ignition. 

•B.  SULPHATES:  Reaction  for  sulphur  with  soda. 

a.  Fusible;  assay  alkaline  after  fusion. 

b.  Fusible;  reaction  for  iron. 

c.  Infusible. 

C.  ARSENATES:  on  coal  arsenical  fumes. 

D.  SILICATES,  PHOSPHATES,  OXIDES. 

Species  not  included  in  the  preceding  subdivisions. 

L    STKEAK  DEEP  RED,   YELLOW,   BROWNISH-YELLOW,  GREEN,  OR 
BLACK. 

A.  Infusible,  or  fusible  with  difficulty. 

B.  Fusible  without  much  difficulty. 

H.    STREAK  GHIAYISH  OR  NOT  COLORED. 

1.   Infusible. 

A.  Gelatinize  with  acid,  forming  a  stiff  jelly. 

B.  Not  forming  a  stiff  jelly;  hydrous. 

a.  Blue  color  with  cobalt  solution. 

b.  Reddish  or  pink  color  with  cobalt  solution. 
e.   Not  blue  or  red  with  cobalt  solution. 


DETERMINATION   OF   MINERALS.  413 

C.  Not  forming  a  stiff  jelly;  anhydrous. 

a.  Blue  color  with  cobalt  solution. 

b.  Not  blue  or  reddish  color  with  cobalt  solution. 

2.  Fusible  with  more  or  less  difficulty. 

A.  Gelatinize  and  form  a  stiff  jelly. 

a.  Hydrous;  fuse  easily. 

b.  Hydrous;  fuse  with  much  difficulty. 

c.  Anhydrous. 

cr.  No  reaction  for  sulphur;  no  coating  on  coal. 
ft.  Reactk  n  for  sulphur  with  soda. 
B    Not  gelatinizing. 

1.  Structure  eminently  micaceous;  folia  tough,  pearly, 

and  H.  of  surface  of  folia  not  over  35;  anhydrous 
or  hydrous. 

2.  Structure  not  eminently  micaceous. 

a.  Hydrous. 

a.  No  reaction  for  phosphorus,  or  boron, 
f.  H.  =  1  to  3;  lustre  not  at  all  vitreous, 
ft.  H.  =3'5-C-5;  lustre  of  cleavage  sur- 
face sometimes  pearly;  elsewhere 
vitreous. 
ft.  Reaction  for  phosphorus  or  boron. 

b.  Anhydrous. 

a.  B.B.  lithium-red  flame. 
ft.  B.B.  boron  reaction  (green  flame). 
y.  B.B.  reaction  for  titanium. 
6.  B.B.  reaction  for  fluorine  or  phosphorus. 
e.   B.B.  reaction  for  iron. 
£.  B.B.  no  reaction  for  iron;  not  of  the  pre- 
ceding subdivisiors. 


I.  ELEMENTS. 

1.  Lustre  metallic;  liquid. 

MERCURY,  p.  143.     This  is  the  only  metallic  mineral  which  is 
liquid  at  the  ordinary  temperature  and  atmospheric  pressure. 

2.  Lustre  metallic;  malleable  and  eminently  sectile. 

GOLD,  p.  122.    G.  =  15-19-5;  yellow;  fusible;  not  sol.  in  nitric  acid 

or  HC1,  but  sol.  in  aqua  regia. 
PLATINUM,  p.  139.     G.  =  16-19;  nearly  white;  infusible;  insol.  in 

nitric  acid. 
PALLADIUM,  p.  141.     G.  =  11  3-ll'8;  grayish- white;  diff.  fusible; 

sol.  in  nitric  acid.  " 
SILVER,  p.  129.     G.  =  10-11 1;  white;  fusible;  sol.  in  nitric  acid, 

and  deposited  again  on  copper. 


414  DETERMINATION   OF  MINERALS. 

COPPER,  p.  145.    G.  =8'84;  copper-reel;  fus.;  sol.  in  nitric  acid, 

and  the  solution  becomes  sky-blue  when  ammonia  is  added. 
IRON,  p.  189.     G.  =  7-3-7-8;  iron-gray;  attracted  by  the  magnet. 

The  only  other  mineral  of  metallic  lustre  that  is  also  malleable  and 
eminently  sectile  is  argentite,  a  silver  sulphide,  along  with  two  others 
of  like  composition  but  different  crystallization. 

3.  Lustre  metallic;  brittle;  B.B.  wholly  volatile,  but  give 

off  no  sulphurous  fumes;  H.  =  2-3*5. 

BISMUTH,  p.  113.     G.  —  9'73;  reddish-white;  on  coal  a  yellow  coat- 
ing; fumes  inod. 

ANTIMONY,  p.  112.     G.  =66-6'7  tin-white;  fumes  dense  wh., 
inod. 

ARSENIC,  p.  110.     G.  =  5-9-6;  tin-white;  fumes  white,  alliaceous. 

TELLURIUM,  p.  108.     G.  =  61-63;  tin-white;  fus. ;  fumes  white; 
flame  green. 
The  only  other  mineral  that  is  wholly  volatile,  and  also  gives  off 

no  sulphurous  fumes,  is  allemontite,  an  antimony  arsenide. 

4.  Lustre  metallic;  H.  =  1-2;  B.B.  on  coal  infusible;  no 

fumes. 

GRAPHITE,  p.  119. 

5.  Lustre  unmetallic;  takes  fire  readily  in  the  flame  of  a 

candle,  and  burns  with  a  blue  flame. 

SULPHUR,  p.  108. 

X6.  Lustre  adamantine;  H.  —10. 
DIAMOND,  p.  115.    Easily  scratches  corundum  or  sapphire. 


II.  MINERALS,  NOT  ELEMENTS,  THAT 

ARE  WHOLLY  VOLATILE  B.B. 

ON  COAL. 

1.  Lustre  metallic;  streak  metallic;  H.  =  1-2. 

TETRADYMITE,  p.  114.  G.=  7'2-7'9;  pale  steel-gray;  so  soft  as 
to  soil  paper;  on  coal  white  fumes;  flame  bluish  green;  sometimes 
sulph.  odor;  in  open  tube,  a  coating  which  fuses  to  white  drops. 

BISMUTHINITE,  p.  114.  G.=  6'4-7'2;  whitish  lead-gray;  on  coal 
yellow  coating  and  sulph.  odor. 

STIBNITE,  p.  112.  G.^4'5-4'52;  lead-gray;  on  coal  dense  wh. 
fumes  and  wh.  coating. 


DETERMINATION  OF  MINERALS.  415 

2.  Lustre  un  metallic;  streak  same  nearly  as  color,  except  in 
cinnabar,  in  which  it  is  always  bright  red.    H.  =  1-3 . 

ORPIMENT,  p.  111.    Lemon  yellow;  on  coal  burns,  odor  alliaceous. 
REALGAR,  p.  111.     Bright  red;  on  coal  burns,  odor  alliaceous. 
ARSENOLITB,  p.  111.     White;  on  coal,  odor  alliaceous. 
VALENTINITE,  p.  113.     White;  on  coal  dense  wh.  fumes,  inod. 
CINNABAR,  p.  143.     Red ;  in  open  tube,  sulph.  odor,  coating  of 

mercury  globules. 
SALMI AK,  p.  249.    White;  saline  and  pungent  taste;  on  coal,  fumes 

of  ammonia. 


III.    COMPOUNDS    OF    GOLD,    SILVER, 
MERCURY,   COPPER,   LEAD,   TIN, 
CHROMIUM,   COBALT,   MAN- 
GANESE. 

A.  Yielding  a  malleable  globule  B.  B.  on  coal,  with  or 
without  soda. 

1.    COMPOUNDS  OP   GOLD. 

Yield  gold,  or  an  alloy  of  gold  and  silver,  B.B.  on  coal. 
The  TELLURIUM  ORES,  pp.  129, 132,  give  a  coating  of  drops  of  tel- 
lurous  acid  in  open  tube  (p.  101). 

2.   COMPOUNDS   OP    SILVER. 

B  B.  easily  fusible;  G.  above  5;  yield,  with  few  exceptions,  a  glo- 
bule of  silver  (white  and  malleable)  on  coal,  with  soda,  if  not  without; 
and,  in  the  exceptions,  silver  globule  obtained  by  cupellation.  All 
have  metallic  lustre  excepting  cerargyrite,  bromyrite,  and  iodyrite. 

a.   EMINENTLY  SECTILE. 

ARGENTTTE,  p.  131.  G.=7'2-7'4;  lustre  metallic;  H.  =  2;oncoal 
sulph.  fumes. 

CERARGYRITE,  p.  134.  H.=  l-2;  G.=  5'3-56;  lustre  like  that 
of  white,  gray,  or  greenish  to  brownish  wax;  see  also  related  spe- 
cies, p.  134. 

6.    NOT   BECTILE  ;    ON  COAL  ODOROUS  FUMES. 

SULPHIDES,  p.  131.     Gives  sulph.  odor. 
ARSENICAL  ORES,  p.  132      Alliaceous  fumes. 
SELENIDES,  p.  131.    Horse  radish  odor. 

C.   NOT  SECTILE  ;    ON  COAL  FUMES  OF  ANTIMONY  OR  TELLURIUM. 

ANTIMONIAL  ORES,  pp.  132,  133.  Dense  white  fumes  of  anti- 
mony; with  also,  if  sulphur  is  present,  sulph.  fumes. 


416  DETERMINATION  OF  MINERALS. 

TELLURIDES,  pp.  131,  132.    In  open  tube  coating  which  fuses  to 

drops  of  tellurous  acid. 
STROMEYERITE,  p.  131.  Contains  copper,  and  requires  cupellation 

in  order  to  obtain  a  globule  of  silver. 

3.   COMPOUNDS   OF    COPPER. 

Unless  iron  is  present,  a  globule  of  metallic  copper  is  obtained  with 
soda,  if  not  without,  on  coal;  with  a  nitric  acid  solution  and  ammonia 
in  excess  a  bright  blue  color;  moistened  with  HC1  the  blue  flame  of 
chloride  of  copper;  and  a  clean  surface  of  iron  in  the  nitric  solu- 
tion becomes  coated  with  copper. 

1.   METALLIC   LUSTRE. 

SULPHIDES,  pp.  148-148.     On  coal  or  in  open  tube  sulph.  fumes; 

H.=  2-4. 

ARSENIDES,  SELENIDES,  p.  149;  H.  =  2-4. 
ANTIMONIAL  SULPHIDES,  pp.  149,  150;  H.=  2-4'5. 

2.  LUSTRE    UNMETALLIC  ;     B.B.    NEITHER    ON    COAL    NOR    IN    OPEN 

TUBE   ANY   ODOROUS  FUMES  ;    NO   TASTE. 

CUPRITE,  p.  151.  H.=  35-4;G.=  58-62;  isometric;  deep  red, 
streak  bnh-red. 

ATACAMITE,  p.  150.  Darkish  bright  green,  streak  guh;  BB.  on 
coal  fuses,  coloring  O.F.  azure-blue,  with  a  green  edge;  easily  sol. 
in  acids. 

PHOSPHATES,  p.  153.     H.=  2-5;  G.=  2 '8-4'5. 

MALACHITE,  p.  154.  H.=  3-4;  G.=  3'7-4;  light  to  deep  green; 
effervesces  with  HC1. 

AZURITE,  p.  156.  H.  =  3  5-4 "5;  G.  =  3  5-3 '9;  deep  blue;  effervesces 
with  HC1. 

DIOPTASE,  p.  156.  H  =  5;  G.=  3!25-3'35;  never  fibrous;  emerald- 
green;  B.B.  infusible. 

CHRYSOCOLLA,  p.  157.    Bluish  green;  B.B.  infusible;  amorphous. 

3.  LUSTRE  UNMETALLIC;  B.B.  ON  COAL,  OR  IN  CLOSED  TUBE,  ODOROUS 

FUMES  OF  ARSENIC  OR  SULPHUR,  OR  REACTION  FOR  SULPHUR. 

ARSENATES,  p.  153.    On  coal  arsenical  fumes;  H.  =  2-3. 
CHALCANTHITE,  p.  152.     Blue;  taste  nauseous;  astringent. 

Also  Stromeyerite,  Stannite,  Bournonite  give  reactions  for  copper. 

4.  COMPOUNDS  OF  LEAD. 

Yield  B.B.  on  coal  a  dark  lemon-yellow  coating;  finally,  with 
soda,  if  not  without,  a  globule  (metallic  and  malleable)  of  lead  is  ob- 
tained; but  by  continued  blowing  with  O.F.  the  lead  all  goes  off  in 
fumes,  leaving  other  more  stable  metals  (silver,  etc.)  behind.  Sul- 
phurous, selenious,  and  tellurous  fumes  easily  obtained  either  on  coal 
or  in  an  open  tube  from  the  sulphide,  selenide,  tellurides;  and  arseni- 
8cal  or  antimonial  fumes  from  ores  containing  arsenic  or  antimony. 
None  have  taste;  none  have  H.  above  4. 


DETERMINATION"   OF   MINERALS.  417 

1.    LUSTRE  METALLIC. 

GALENITE,  p.  160.  H.  =  2 '5;  G.  =  7'2-7'7  ;  cleavage  cubic  emi- 
nent ;  lead -gray,  streak  same  ;  in  open  tube  sulpli. 

SELENIDES,  TELLURIDES,  ANTIMONIAL  and  ARSENI- 
CAL SULPHIDES,  pp.  160-164. 

2.    LUSTBE    UNMETALLIC  ;    NO  ODOROUS    FUMES,   OR    REACTION    FOR 
SULPHUR. 

MINIUM,  p.  165.     Bright  red,  streak  same. 

CROCOITE,  p.  166.     Monoclinic ;  bright  red,  streak  orange-yellow; 

B.B.  with  salt  of  phosphorus  emerald-green  bead. 
PYROMORPHITE,   p.    167.     Hexagonal,  6-sided   prisms ;  bright 

green,  brown,  rarely  orange-yellow  ;    streak  white.     B.B.    fuses 

easily,  coloring  flame  bluish  green. 
VANADINITE,  p.  168.     Hexagonal  prisms,  like    pyromorphite ; 

G.  =  6 '6-7*2  ;  yellow,  bnh-yw,  straw  yellow.     B.B.  fuses  easily, 

reaction  for  vanadium. 
CERUSSITE,  p.  168.     Orthorhombic,  often  in  twins  ;  H.  =  3-3 '5  ; 

G.  —  6 '4-6*8 ;  white,  gyh  ;  lustre  adamantine  ;  often  tarnished  to 

grayish  metallic  adamantine.    Effervesces  in  dilute  nitric  acid. 

3.   UNMETALLIC  J  REACTION  FOR  SULPHUR. 

ANGLESITE,  p.  165.  Orthorhombic;  white,  gyh;  fuses  in  flame 
of  candle;  B.B.  reaction  for  sulphur;  no  effervescence  with  acids. 


5.  COMPOUNDS  OF  TIN. 

CASSITERITE,    p.    176.     H.  =  6-7  ;    G.  =  6'4-7'l ;    tetragonal ; 

brown,  gyh,  ywh,  black;  B.B.  infusible;  on  coal  with  soda  a  globule 

of  tin,  yield  no  fumes. 

Stannite,  p.  176.    A  copper,  iron,  and  tin  sulphide,  does  not  give 
B.B.  a  metallic  malleable  globule. 

B.  Yields  drops  of  mercury  in  closed  tube  with  or 
without  soda. 


COMPOUNDS  OF  MERCURY. 

CINNABAR,  p.  143.    H.  =  2-2 '5;  G.  =  8-9;  rhombohedral;  bright 

red,  bnh  red,  gyh;  streak  scarlet. 
AMALGAM,  p.  130.     H.  =  3-3 '5;  G.  =  13-14;  silver-white;  yields 

silver  B.B.  on  coal. 

A  variety  of  tetrahedrite,  p.  150,  yields  mercury. 

C.  No  malleable  globule ;  decisive  reaction  with  borax  or 
salt  of  phosphorus  for  chromium,  cobalt,  or  manganese. 

27 


418  DETERMINATION   OF   MINERALS. 

1.  COMPOUNDS  OF  CHROMIUM. 

Give  with  borax  an  emerald-green  bead  in  both  flames. 

CHROMITE,  p.  197.  H.  =  5'5  ;  G.  =  4  3-4'5  ;  isometric,  often  in 
octahedrons,  massive  ;  submetallic  ;  bnh  iron-black,  streak  brown  ; 
B.B.  on  coal  becomes  magnetic;  with  borax,  a  bead  which  is 
emerald-green  on  cooling. 

CROCOITE,  p.  166.  H.  =  25-3  ;  G.  =  5D-61 ;  monoclinic  ;  bright 
red,  streak  orange;  B.B.  fuses  very  easily,  on  coal  globule  of  lead, 
and  with  salt  of  phosphorus  emerald  green  bead.  Plwnicochroite 
and  Vauquelinite  are  other  lead  chromates. 

2.  COMPOUNDS  OF  COBALT. 

Give  a  blue  color  with  borax  after,  if  not  before,  roasting. 

[When  much  nickel  or  iron  is  present  the  blue  color  is  not  ob- 
tained; and  species  or  varieties  of  this  kind  are  not  here  included.] 

1.    LUSTRE  METALLIC. 

COBALTTTE,  p.  182.  H,  =  5 '5;  G.  =  6-6  3;  isometric  and  pyrito- 
hedral;  rdh  silver-white,  streak  grayish  black;  B.B.  on  coal  sulph. 
and  arsen.  fumes,  and  a  magnetic  globule. 

SMALTITE,  p.  181.  H.  =  5'5-6  ;  G.  =  6'4-7'2  ;  isometric;  tin- 
white,  streak  gyh  black  ;  B.B.  on  coal  alliaceous  fumes  ;  most 
varieties  fail  to  give  the  blue  color  immediately  with  borax,  because 
of  the  iron  and  nickel  present. 

LINNJEITE,  p.  181.  H.  =  5'5  ;  G.  =  4'8-5  ;  isometric  ;  pale  steel- 
gray,  copper-red  tarnish,  streak  bkh  gray.  B.B.  on  coal  sulph. 
fumes. 

2.   LUSTRE  UNMETALLIC. 

ERYTHRITE,  p.  184.  H.  =  l'5-2'5  ;  G.  =  2'95  ;  monoclinic,  one 
highly  perfect  cleavage,  also  earthy;  rose-red,  peach-blossom  red, 
streak  reddish;  B.B.  fuses  easily;  yields  water. 

BIEBERITE,  p.  185.     A  cobalt  sulphate. 

REMINGTONITE,  p.  185.    A  hydrous  cobalt  carbonate. 

3.  COMPOUNDS  OF  MANGANESE. 

Give  an  amethystine  globule  in  O.F.  with  borax.  [The  globule 
looks  black  if  too  much  of  the  manganese  mineral  is  used,  and  with 
a  large  excess  may  be  opaque.] 

1.    GIVES  OFF  CARBONIC  ACID  WHEN    TREATED  WITH  DILUTE  HC1  ; 
LUSTRE   UNMETALLIC. 

RHODOCHROSITE,  p.  210.    H.  =  3'5-4'5;  G.  =  3'4-3'7;  rose-red. 

Also  manganese-bearing  varieties  of  calcite,  dolomite,  ankerite,  side- 
rite,  all  of  which  have  the  cleavage  and  general  form  of  rhodochro- 
site ;  when  containing  one  per  cent,  or  more  of  manganese  they  often 
turn  black  on  exposure. 


DETERMINATION   OF   MINERALS.  419 

2.    TREATED  WITH  HC1  YIELDS  CHLORINE  FUMES. 

MANGANITE,  p.  207.  H.  =  4  ;  G.  =  4'2-4'4  ;  in  oblong  ortho- 
rhombic  prisms  ;  grayish  black,  streak  reddish  brown  ;  lustre  sub- 
metallic  ;  B.B.  infusible ;  yields  water. 

PSILOMELANE,  p.  207.  H.  =  5-7  ;  G.  =  3'7-4'7  ;  amorphous  ; 
black,  streak  brownish  black  ;  submetallic;  B.B.  infusible;  yields 
water. 

Wad  is  similar,  but  often  contains  cobalt. 

PYROL.USITE,  p.  206.  H.  =  2-2 '5  ;  G.  =  4'82  ;  in  stoutish  ortho- 
rhombic  crystals;  metallic;  dark  steel-gray,  streak  black  or  bluish 
black;  B.B.  infusible;  yields  no  water. 

BRAUNITE  and  HAUSMANNITE  (p.  207)  are  other  anhydrous 
manganese  oxides. 

FRANKLINITE,  p.  197.  H.  =  5'5-6'5  ;  G.  =  5-5'l  ;  in  isometric 
octahedrons  and  massive  ;  iron-black,  streak  dark  reddish  brown  ; 
B.B.  infusible  ;  but  little  chlorine  with  HC1 ;  sometimes  a  little 
magnetic. 

3.    CO2   OR   Cl  NOT  GIVEN  OFF  WHEN  TREATED  WITH  HC1  ; 
ANHYDROUS. 

RHODONITE,  p.   268.     H.  =  5'5-6'5  ;   G.  =  3'4-3'68  ;   rose-red  ; 

B.B.  fuses  easily. 
TRIPLITE,  p.  209.     H.  =  5'5;  G.  =  3'4-3'8;  brown  to  black;  B.B. 

fuses  very  easily,  globule  magnetic;  sol.  in  HC1. 
HEI/VTTE,  p.  278.    H.  =  6-6 '5;  G.  =  3 1-3 '3;  in  yellowish  tetrahe- 

hedrons;  B.B.  fuses  easily. 
SPESSARTITE  (Manganesian  Garnet),  p.  279.    H.  =  6*5-7  ;  G.  = 

3'7-4'4  ;  in  dodecahedrons  and  trapezohedrons;  red,  brownish  red; 

B.B.  fuses  easily. 
TEPHROITE,  p.  277.     H.  =  5'5-6  ;  G.  =  4-4'12  ;  orthorhombic  ; 

reddish  to  brown  and  gray;  B.B.  fuses  not  very  easily;  gelat.  in 

HC1. 

Knebelite,  p.  277,  is  related,  and  also  gelatinizes. 
HAUERITE,  p.  206.    H.  —  4;  G.  =  3 '46;  isometric;  reddish  brown, 

streak  brownish  red.     B.B.  yields  sulphur,  after  roasting  reaction 

for  manganese. 

ALABANDITE,  p.  206.  H.  =  3 '5-4  ;  G.  =4;  submetallic,  iron- 
black;  streak  green;  B.B.  on  coal  sulphur,  after  roasting  reaction 

for  manganese. 

Vesuvianite,  epidote,  axinite,  ilvaite,  gothite,  include  varieties  that 
give  reaction  for  manganese. 


420  DETERMINATION   OF  MINERALS. 


IV.  MINERALS  OF  METALLIC  OR  SUB- 
METALLIC  LUSTRE  NOT  INCLUDED 
IN  PRECEDING  DIVISIONS. 


1.    YIELDING   FUMES  IN  THE   OPEN  TUBE  OR 
ON  COAL,  BUT  NOT  WHOLLY  VAPORIZABLE. 

A.  STREAK  METALLIC  ;  H.  =  1-2. 

MOLYBDENITE, p.  108.  H.  =  1-1-5;  G.  =  4 '4-4-8;  lead-gray,  and 
leaves  trace  on  paper;  B.B.  on  coal  sulphurous  fumes. 

BISMUTHINITE,  p.  114.  H.  =  2;  G.  =  6'4-7'2;  lead-gray,  whitish; 
B.B.  on  coal  sulphurous  fumes,  and  yellow  bismuth  oxide;  sol.  in 
hot  nitric  acid  and  a  white  precip.  on  diluting  with  water. 

s 
B.  STREAK  UNMETALLIC. 

a.   FUMES  SULPHUROUS  ONLY. 

PYRITE,  p.  192.  H.  =  6-65;  G.  =  4 '8-5-2;  isometric,  most  com- 
mon in  cubes,  the  faces  of  which  sometimes  smooth,  often  striated, 
the  striae  of  adjoining  faces  meeting  at  right  angles,  often  in  pyrito- 
hedrons;  pale  brass  yellow,  streak  gnh  black,  bnh  black;  B.B.  on 
coal,  fuses  to  a  magnetic  globule. 

MARCASITE,  p.  191,  H.  =  6-6'5;  G.  =  4.68-4'85;  orthorhombic; 
pale  bronze-yellow;  streak  gyh  black,  bnh  black;  B.B.  like  pyrite. 

PYRRHOTITE,  p.  192.  H.  =  S'5-4'5  ;  G.  =  4'4-4'68  ;  hexagonal; 
bronze-yellow,  rdh  ;  streak  gyh  black  ;  slightly  magnetic  ;  B.B. 
fuses  to  a  magnetic  mass. 

MILLERITE,  p.  181.  H.  =  3-3'5  ;  G.  =  4'6-5'7  ;  rhombohedral, 
usually  in  acicular  or  capillary  forms,  also  in  fibrous  crusts;  brass- 
yellow,  somewhat  bronze-like;  B.B.  fuses  to  a  globule,  reacts  for 
nickel. 

LINN^JITE,  p.  181.  H.  — 5*5  ;  G.  =  4*8-5  ;  isometric  ;  pale  steel- 
gray,  copper-red  tarnish;  streak  blackish -gray;  B.B.  on  coal  fuses 
to  a  magnetic  globule,  after  roasting  gives  reactions  for  nickel, 
cobalt,  and  iron. 

SPHALERITE,  p.  170.  H.  =  3'5-4;  G.=  3'9-4'2;  isometric; 
bright  and  easy  dodecahedral  cleavage  when  cryst. ;  lustre  sub- 
metallic  ;  color  black  ;  streak  nearly  uncolored ;  nearly  infusible 
alone  and  with  borax;  on  coal  a  coating  of  zinc  oxide. 

b.   ABSENICAL  FUMES,   WITH  OR  WITHOUT   SULPHUROUS. 

ARSENOPYRITE,  p.  192.  H.  =  5-6  ;  G.  =  6-6'4  ;  orthorhombic ; 
white,  gyh,  streak  dark  gyh  black.  In  closed  tube,  red  arsenic 


DETERMINATION  OF  MINERALS. 

sulphide  and  metallic  arsenic ;  B.B.  on  coal  fuses  to  magnetic 
globule. 

GERSDORFFITE,  p.  183.     H.^5'5;  G.=  5-6-6'9;  isometric,  py- 

,  ritohedral ;  white,  gyh,  streak  grayish  black.  In  closed  tube 
arsenic  sulphide,  on  coal  not  magnetic,  and  reacts  for  nickel  and 
often  cobalt. 

NICCOLITE,  p.  182.  H.=  5-§'5  ;  G.  =  7 '3-7 "7  ;  hexagonal ;  pale 
copper-red,  streak  pale  bnh  black  ;  in  open  tube,  coating  of  arsen- 
ous  acid;  B.B.  on  coal  no  sulph.  fumes,  fuses  to  globule  which  re- 
acts for  iron,  cobalt  and  nickel. 

SMALTITE,  p.  181.  H.=  5'5-6;  G.=  6'4-7'2;  isometric;  tin- 
white  ;  streak  gyh  black ;  on  coal,  no  fumes  of  sulphur  or  only  in 
traces. 


2.  NOT  YIELDING  FUMES  OF  ANY  KIND. 
STKEAK  UNMETALLIC. 

A.    B.B.   EASILY  FUSIBLE,  AND    GIVING  A  MAGNETIC 
BEAD.     LUSTRE  SUBMETALLIC. 

ILVAITE,  p.  285.  H.=  5'5-6  ;  G.=  3'7-4'2  ;  orthorhombic  ;  gyh 
iron-black,  streak  gnh  or  bnh  black;  gelat.  with  HC1. 

ALLANITE,  p.  284.  H.=  5'5-6;  G.=  3-4'2;  monoclinic ;  bnh 
pitch-black,  streak  gyh,  bnh ;  B.B.  fuses  easily ;  most  varieties 
gelat.  with  HC1. 

WOLFRAMITE,  p.  200.  H.=  5-5'5  ;  G.=  7'l-7'6  ;  monoclinic  ; 
gyh  black  or  bnh  black  ;  B.B.  fuses  easily,  and  reacts  for  iron,  man- 
ganese, and  tungsten. 

B.    INFUSIBLE  OR  NEARLY  SO. 

a.   REACTION  FOR  IRON  ;  ANHYDROUS  ;   H.  =  5-6'5. 

MAGNETITE,  p.  196.  G.  =  4'9-5'2  ;  isometric  ;  iron-black  ; 
streak  black;  strongly  magnetic. 

MENACCANITE,  p.  195.  G.  =  4'5-5;  rhombohedral;  iron-black; 
streak  submetallic,  black  to  bnh  red;  very  slightly  magnetic. 

HEMATITE,  p.  193.  G  —  4'5-5'3;  rhombohedral;  gyh  iron-black, 
in  very  thin  splinters  or  scales  blood-red  by  transmitted  light; 
streak  red;  sometimes  slightly  magnetic. 

MARTITE,  p.  194.     Same  as  hematite,  but  isometric. 

TANTALITE,  p.  202.  G.  =  7-8  ;  orthorhombic  ;  iron-black,  streak 
rdh  brown  to  black. 

FRANKLINITE,  p.  197.  H.=  5'5-6'5  ;  G.=  4'8-5'l  ;  octahedral, 
massive  ;  iron-black  ;  streak  dark  rdh  brown  ;  slightly  attracted  by 
magnet;  with  soda  reaction  for  manganese. 

COLUMBITE,  p.  207.  G.  =  5'4-6'5;  orthorhombic;  iron  black, 
gyh  black,  streak  dark  red  to  black,  often  with  a  bluish  steel- 
like  tarnish. 

SAMARSKITE,  p.  221.  H.=  5'5-7;  G.=  5'6-5'8;  velvet-black, 
pitch-black ;  streak  dark  rdh  brown  ;  B.B.  glows ;  fuses  with  diffi- 
culty. 


422  DETERMINATION"   OF   MINERALS. 

b.   BEACTION  FOB  IRON  ;   HYDROUS  ;   LUSTRE   SUBMETALLIC. 

LIMONITE,  p.  198.  G.  =  3'6-4;  not  in  crystals;  massive,  often 
stalactitic  and  tuberose  with  surface  sometimes  highly  lustrous  ; 
often  subfibrous  in  structure  ;  black,  bnh  black;  streak  bnh  yellow, 
which  becomes  red  on  heating. 

GOTHITB,  p.  199.  G.  =  4'0-4'4  ;  orthorhombic  ;  also  fibrous  and 
massive;  bkh  brown;  streak  bnh  fellow. 

TURGITE,  p.  199.  G.=  3'6-4'68  ;  fibrous  and  massive,  looking 
like  limonite  ;  black,  rdh  black,  streak  red  ;  in  closed  tube  decrepi- 
tates, which  is  not  the  case  with  gothite  and  limonite. 

C.   REACTION  FOR  CHROMIUM  OR  TITANIUM. 

CHROMITE,  p.  197.     H.=  5-5;  G.=  4'3-4'6;  isometric;  submetal- 

lic  ;  bnh  iron -black,  streak  brown ;  B.B.  with  borax  gives  a  bead 

which  on  cooling  is  chrome-green. 
RUTILE,  p.  179.     H.=  6-6'5  ;  G.=  4'18-4'25  ;   black,  streak  bnh  ; 

reacts  for  titanium.     Black  varieties  of  brookite  (p.  180),  submetallic 

in  lustre,  give  same  reaction. 

Euxenite,  p.  222;  yttrotantalite,  p.  221;  ceschynite,  p.  222;  ferguson- 
ite,  p.  221 ;  and  perofskite,  p.  180,  are  submetallic  in  lustre. 

d.   HEATED  WITH  NITRE  IN  A  MATRASS  YIELDS  FUMES  OF  OSMIUM. 

IRIDOSMINE,  p.  141.  H.  =  6-7;  G.=  19-21'2;  in  small  scales 
from  auriferous  or  platiniferous  sands;  tin-white,  gyh. 


V.  LUSTRE  UNMETALLIC. 

1.    MINERALS    HAVING    AN    ACID,   ALKALINE, 
ALUM-LIKE,    OR  STYPTIC   TASTE. 

A.  CARBONATES:    Taste  alkaline;  effervescing  with  HC1. 

NATRON,  p.  249.     Eflloresces  on  exposure. 
TRONA,  p.  249.     Does  not  effloresce. 

B.  SULPHATES :   No  effervescence ;  reaction  B.B.  on  coal  with 
soda  for  sulphur. 

MASOAGNITE,  p.  250.    Yields  ammonia. 

MIRABLLITE,    p.    246.    Monoclinic,  crystals    stout;    taste    cool, 

saline,  bitter;  B.B.  flame  deep  yellow. 
EPSOMITE,  p.  224.     Orthorhombic,   crystals  ordinarily  slender, 

spicule-like;  taste  bitter  and  saline;  B.B.  flame  not  yellow. 
ALUNOGEN,  p.  216.     Taste  like  common  alum. 
KALINITE,  MENDOZITE  and  other  alums,  p.  217. 
MELANTERITE,  p.  199.     Green  ;  taste  styptic ;  reacts  for  iron. 
CHALCANTHITE,  p.  152.    Blue  ;  reacts  for  copper. 


DETERMINATION    OF   MINERALS.  423 

MORENOSITE,  p.  185.     Green ;  reacts  for  nickel. 
BIEBERITE,  p.  185.    Reddish  ;  reacts  for  cobalt. 
GOSLARITE,  p.  172.     White  ;  reacts  for  zinc. 
JOHANNITE,  p.  188.     Emerald-green,  reacts  for  uranium. 

C.  NITRATES :    With  sulphuric  acid,  reddish  acrid  fumes ;   no 

action  with  hydrochloric  acid;  deflagrate. 

NITRE,  p.  247.     Not  efflorescent.     Strong  deflagration. 
NITRATINE,  SODA-NITRE,  p.  248.     Efflorescent. 
NITROCALCITE,  p.  234.    Deflagration  slight. 

D.  CHLORIDES :  With  sulphuric  acid  acrid  fumes  of  HC1 ;   no 

fumes  with  HC1. 

SALMI AK,  p.  249.     Taste  saline,  pungent ;    on  coal,  evaporates  ; 

with  soda,  odor  of  ammonia. 

SYLVITE,  p.  243.     Taste  saline  ;  B.B.  flame  purplish. 
HALITE  or  COMMON  SALT,  p.  243.     Taste  saline  ;  B.B.  flame 

yellow. 

E.  BORATES.     No  effervescence  with  acids;  B.B.  reaction  for 

boron,  when  moistened  with  sulphuric  acid. 

SASSOLITE,  p.  109.     Taste  feebly  acid  ;  B.B.  very  fusible. 
BORAX,  p.  246.    Taste  sweetish  alkaline;  B.B.  puffs  up. 


2.  MINERALS   NOT    HAVING    AN    ACID,   ALKA- 
LINE, ALUM-LIKE  OR  STYPTIC   TASTE. 

A.  CARBONATES:  Effervescing  with  HC1. 

A.    INFUSIBLE  ;  ASSAY  ALKALINE  AFTEB  IGNITION. 

CALCITE,  p.  234.  H.  under  3'5;  G.  =  2-5-2.72;  E  A  R  =  105°  5', 
with  three  easy  cleavages  parallel  to  R;  colors  various  ;  effevesces- 
readily  with  cold  HC1 ;  anhydrous. 

ARAGONITE,  p.  237.  H.  =  3'5-4 ;  G.  =  2*94  ;  orthorhombic,  cleav- 
age imperfect;  otherwise  like  calcite. 

DOLOMITE,  p.  238.  H.=  3'5-4;  G.=2'8-29;  rhombohedral, 
R  A  -5  =  106°  15';  colors  various;  effervesces  but  slightly  with  cold 
HC1,  unless  finely  pulverized;  anhydrous. 

MAGNESITE,  p.  226.  H.  =  3'5-4'5;  G.  =  3-3'l;  rhombohedral, 
B  A  -5  =  107°  29';  white,  ywh,  gyh;  effervesces  but  slightly  with 
cold  HC1 ;  anhydrous. 

HYDROMAGNESITE,  p.  224.  H.=  l-3'5;  G.=  2'14-2  18 ; 
hydrons. 


424  DETERMINATION   OF   MINERALS. 


B.   INFUSIBLE;    BECOME  MAGNETIC  AND  NOT  ALKALINE    AFTEB 
IGNITION. 

SIDERITE,  p.  203.      H.=  3'5-4-5;    G.  =  3'7-39;    rhombohedral, 

B:R  —  107° ;  cleavage  as  in  calcite  ;  becomes  brown  on  exposure, 

changing  to  limonite. 
ANKERITB,  p.  204.     H.  =  3'5-4  ;  G.  =  2'9-31 ;  R  A  R  =  106°  7'; 

becomes  brown  on  exposure. 

Some  kinds  of  calcite  and  dolomite  contain  iron  enough  to  become 
magnetic  on  ignition. 

C.   INFUSIBLE  ;  B.B.    ON   COAL  WITH   SODA,  COATING  OF  ZINC  OXIDE. 

SMITHSONITE,  p.  172.  H.=  5;  G.=  4r4'5;  rhombohedral  like 
calcite  ;  B  A  -R  —  107°  40';  crystals  often  an  acute  rhombohedron  ; 
anhydrous. 

HYDROZINOITE,  p.  173.  H.=  2-2'5  ;  G.=3'6-3-8  ;  white,  gyh, 
ywh,  often  earthy ;  reacts  for  zinc  ;  hydrous. 

D.  INFUSIBLE;  B.B.  ON  COAL  REACTION  FOB  NICKEL. 

ZARATITE  (Emerald  nickel),  p.  185.  H.  —  3.  Emerald  green, 
streak  paler. 

E.    FUSIBLE  ;     ASSAY  ALKALINE  AFTEB  IGNITION. 

WITHERITE,  p.  241.    H.  =  3-3'75  ;  G.  =  4'29-4'35  ;  orthorhombic  ; 
white,  ywh,  gyh;  B.B.  fuses  easily,  flame  ywh  green ;  anhydrous. 
STRONTIANITE,  p.  242.     H.=  3'5-4  ;  G.=  3'6-3'72  ;  orthorhom- 
bic ;  pale  green,  gray,  ywh,  white  ;  B.B.  fuses  only  on  thin  edges, 
flame  bright  red  ;  anhydrous. 

BARYTOCALCITE,  p.  242.  Monoclinic.  G.=  36-3'66;  B.B. 
nearly  like  witherite. 

Other  carbonates  are  the  Lead  Carbonate,  p.  168,  and  Copper  Car- 
bonates, p.  154,  156,  included  severally  under  the  heads  of  LEAD  and 
COFFEE,  on  pages  416,  417. 


B.  SULPHATES  or  SULPHIDES :  Reaction  for  Sulphur 
with  Soda. 

A.   FUSIBLE  ;  ASSAY  ALKALINE  AFTEB  FUSION. 

BARITE,    p.    240.      H.=  2'5-3'5;    G.^4'3-4'72;    orthorhombic; 

white,  ywh,  gyh,  bluish,  brown  ;   B.B.  decrepitates  and  fuses ; 

flame  yellowish  green  ;  anhydrous. 
CELESTITE,  p.  242.     H.  =  3-3'5;   G.=  3'9-3'98;  orthorhombic; 

white,  pale  blue,  rdh  ;  B.B.  fuses  ;  flame  red  ;  anhydrous. 
ANHYDRITE,  p.  230.     H.^3-3'5;    G.  =  2.9-3'0;   orthorhombic, 

with  three  rectangular  and  easy  cleavages  differing  but  slightly ; 

white,  bluish,  gyh,  rdh,  red ;  B.B.  fuses,  flame  reddish  yellow. 
GYPSUM,    p.   229.     H.  =  l'5-2;    G.  =  2'3-2'35;    monoclinic,   one 

perfect,  pearly  cleavage  ;  white,  gray,  but  also  brown,  black  from 


DETERMINATION   OF   MINERALS.  425 

impurities;  B.B.  yields  much  water,  becomes  white  and  crumbles 
easily. 

B.   FUSIBLE  ;  REACTION  FOR  IRON. 

COPIAPITB,  p.  200.     H.  =  1  '5 ;   G.  =  2  14  ;  yellow  ;   on  coal,  be- 
comes magnetic ;  hydrous. 
Hauynite,  p.  294,  also  gives  the  sulphur  reaction  with  soda. 

C.   INFUSIBLE,    OR  NEARLY  SO. 

ALUMINITB,  p.  218.     H.  =  1-2  ;  G.  =  1  '66  ;  adheres  to  the  tongue; 

white  ;  B.B.  blue  with  cobalt  solution.     Alunite.  p.  198,  is  similar, 

but  H.  =  4,  and  G.=  2'58-2'75. 
SPHALERITE,  p.  170.     H.  =  3 '5-4  ;  G.  =  3'9-4'2  ;   isometric,  easy 

dodecahedral  cleavage  when  cryst. ;  light  to  dark  resin-yellow  and 

brown  to  gyh  white;  B.B.  on  coal,  coating  of  zinc  oxide. 

C.  ARSENATES :  Arsenical  fumes  on  coal. 

SCORODITE,  p.   203.     H.=  3'5-4;    G.=  3'l-3'3;    orthorhombic  ; 

leek-green  to  liver-brown;  B.B.  fuses  easily,  flame  blue,  and  with 

soda  gives  a  magnetic  bead  ;   on  coal  alliaceous  fumes ;  in  HC1 

sol. 
PHARMACOSIDERITE,  p.  203.     H.=  2'5;    G.=  29-3;    cubes 

and  tetrahedrons ;   dark  green,  bnh,  reddish ;   B.B.  same  as  for 

scorodite. 
PHARMACOLITE,  p.  234.     H.=  2-2'5  ;  G.=  2'6-2'75  ;  wh,  gyh, 

rdh  ;   monoclinic  with  one  eminent  cleavage ;  B.B.  fuses,  flame 

blue ;  on  coal,  alliaceous  fumes ;  after  ignition  assay  alkaline ;  in 

HC1  sol. 


D.  SILICATES,  PHOSPHATES,  OXIDES  :  SPECIES  NOT 
INCLUDED  IN  THE  THREE  PRECEDING  SUBDIVI- 
SIONS. 

I.  Streak  deep  red,  yellow,  brownish  yellow,  green  or  black. 
A.  INFUSIBLE,  OR  FUSIBLE  WITH  MUCH  DIFFICULTY. 

HEMATITE,  p.  193.  Rhombohedral ;  red  to  black  ;  streak  red  ; 
B.B.  reaction  for  iron;  magnetic  after  ignition  in  R.F.;  anhy- 
drous. 

LIMONITE,  p.  198.  Brownish  and  ochre-yellow  to  black ;  streak 
brownish-yellow ;  B.B.  gives  off  water,  turns  red,  becomes  mag- 
netic in  R.F. 

TURGITE,  p.  199.  Brown  to  black;  streak  red;  B.B.  gives  off 
water  ;  decrepitates  ;  becomes  magnetic  in  R.F. 

FERGUSONITE,  p.  221.     Brownish  black;  infusible. 

ZINCITE,  p.  171.  Red ;  streak  orange  ;  B.B.  on  coal,  zinc  oxide 
coating,  and  coating  moistened  with  cobalt  solution,  green  in  R.F. 


426  DETERMINATION   OF   MINERALS. 

B.  FUSIBLE  WITHOUT  MUCH  DIFFICULTY. 

WOLFRAMITE,  p.  200.  Grayish  to  brownish  black  ;  streak  dark 
reddish  brown  to  black ;  lustre  submetallic  ;  Gr.=  7'l-7'55.  B.B. 
fuses  easily,  and  becomes  magnetic  ;  reaction  for  tungsten. 

VIVIANITE,  p.  202.  Blue  to  green  (to  white);  streak  bluish  white; 
G.  —  2'5-2'7  ;  H.=  1*5-2,  hydrous  ;  B.B.  fuses  easily  to  magnetic 
globule,  coloring  flame  bluish  green. 

TORBERNITE,  p.  187.  Bright  green,  square  tabular  micaceous 
crystals  ;  streak  paler  green  ;  H.=  2-2'5  ;  hydrous  ;  yields  a  glob- 
ule of  copper  with  soda. 

SAMARSKITE,  p.  221.  H.^5'5-6;  G.=  5'6-5'8;  velvet  black; 
streak  dark  reddish  brown;  B.B.  fuses  on  the  edges. 

II.  Streak  grayish  or  not  colored. 
1.  INFUSIBLE. 

A.    GELATINIZE  WITH  ACID,  FORMING  A  STIFF  JELLY. 

CHRYSOLITE,  p.  277.  Yellow-green  to  olive-green,  looking  like 
glass;  H.=  6'7;  G.=  3'3-3'5;  B.B.  reacts  for  iron,  becomes  mag- 
netic; anhydrous. 

CHONDRODITE,  p.  303.  H.=6-6'5  ;  G  -3'l-3'25  ;  pale  yellow 
to  brown,  and  garnet-red;  lustre  vitreous  to  resinous;  B.B.  reac- 
tion for  iron  and  fluorine;  anhydrous. 

ALLOFHANE,  p.  318.     H.=  3  ;  G.—  l'S-1'9  ;  always  amorphous, 
never  granular  in  texture ;  bluish,  greenish ;  B.B.  infus.,  a  blue 
cotor  with  cobalt  solution;  hydrous. 
Wttlemite,  Calamine,  Sepiolite,  fuse  with  great  difficulty,  and  are 

included  under  fusible  gelatinizing  species,  pp.  428,  429. 

B.    NOT  FORMING  A  STIFF  JELLY  WITH  ACID  ;     HYDROUS. 

a.  Blue  with  cobalt  solution  (owing  to  presence  of  aluminium). 

WAVELLITE,  p.  220.     H.=  3'25-4;  G.  =  2'3-2'4;  white  to  green, 

brown;  B.B.  bluish  green  flame  after  moistening  with  sulph.  acid. 
LAZULITE,    p.    218.      H.  =  5'6;   G.=  3-3'l;   blue;    B.B.   green 

flame,  especially  after  moistening  with  sulph.  acid;  hydrous. 
TURQUOIS,  p.  219.     H.=  6  ;   G.=2'6-2'85  ;  sky-blue,  pale  green  ; 

B.B.  flame  green. 
KAOLINITE,  p.  232.     H.=  1-2  ;  G.=2'4-2'65  ;  white  when  pure  ; 

feel  greasy;  B.B.  flame  not  green. 
GIBB8ITE,  p.    213.    H.^2'5-3'5;   G.=  2'3-2'4;   white,   grayish, 

greenish;  B.B.  flame  not  green;  soluble  in  strong  sulph.  acid. 
DIASFORE,   p.  213.     H.=  6'5-7;  G.^3'3-3'5;  in   thin  foliated 

crystals,  plates  or  scales ;  white,  greenish,  brownish  ;   B.B.  flame 

not  green;  soluble  in  sulphuric  acid  after  ignition. 

&.  Pale  red  or  pink  color,  with  cobalt  solution  (owing  to  presence 
of  magnesium). 

BRUOITE,  p.  223.  H.=  2'5 ;  G.  =  2'3-2'45  ;  pearly,  white,  green- 
ish;  foliaceous  or  fibrous  and  flexible;  B.B.  after  ignition,  alkaline. 


DETERMINATION   OF   MINERALS.  427 

c.  Not  blue  or  red  with  cobalt  solution. 

OPAL,  p.  259.     H*=  5-5-6-5  ;  Q,=  l'9-2'3  ;   B.B.  with  soda  soluble 

with  effervescence. 
GENTHITE,  p.  332.     H.^3-4;    G.  =  2'4;  pale  green,  yellowish; 

B.B.  with  borax  a  violet  bead,  becoming  gray  in  R.F.  owing  to 

nickel;  decomp.  by  HC1. 
CHRYSOCOLLA,  p.  157.     H.  =  2-4;  G.  =  2-2'24;  pale  bluish  green 

to  sky-blue  ;    B.B.  flame  emerald-green,  and  with  soda  on  coal 

globule  of  copper. 

The  micas,  chlorites,  chloritoid,  and  serpentine  often  fuse  on  their 
edges  with  much  difficulty. 

C.    NOT  FORMING  A  STIFF  JELLY;  ANHYDROUS.      H.  =  5  tO  9. 

a.  Blue  color  with  cobalt  solution. 

CORUNDUM,  p.  211.     H.=  9;  G.=  4;  rhombohedral;  blue,  white, 

red,  gray,  brown. 

CHRYSOBERYL,p.215.   H.=  8'5;  G.  =  3'7;  orthorhombic ;  gray- 
ish green,  to  emerald-green,  brown. 
TOPAZ,  p.  309.     H.=  8 ;  G.—  3*5  ;  in  rhombic  prisms  with  perfect 

basal  cleavage,  rarely  columnar ;  white,  wine-yellow,  and  other 

shades. 
RUBELLITE,  p.  305  ;     H.=  7'5;  G.=  3 ;  in  prisms  of  3,  6,  or  9 

sides-  rose-red;  reaction  for  boron. 
ANDALUSITE,  p.  306.     H.  =  7'5  ;  G.  =  3'2  ;  orthorhombic;  always 

in  prismatic  crystals,  often  tessellated  within,  /A  1=  93°;  grayish 

white  to  brown. 
FIBROLITE,  p.  307.     H.  —  6-7  ;  G.  =  3 '2  ;  orthorhombic  columnar 

or  fibrous  forms  and  prismatic  crystals  with  brilliant  diag.  cleavage. 
CYANITE,  p.  308.     H.=  5-7  (greatest  on  extremities  of  crystals); 

G.=  3'6;  in  long  or  short  prismatic  triclinic  crystallizations,  often 

bladed  prisms;  pale  blue  to  white  and  gray. 
LEUCITE,  p.  295.      H.=  5'5-6;  G.=  2'5;  often  in  trapezohedral 

crystals;  white,  gyh. 

b.  Not  giving  a  blue  or  reddish  color  with  cobalt  solution  j  H.  = 

8  to  5. 

SPINEL,  p.  213.  H.  =  8;  G.  =  3-5-4 -1 ;  in  octahedrons  of  red,  green- 
ish, gray,  black  colors;  sometimes  dodecahedral.  Gahnite  is  simi- 
lar, but  with  borax  on  coal,  gives  reaction  for  zinc. 

BERYL,  p.  274.  H.  =  7'5-8;  G.  =  2'6-2'7;  always  in  hexagonal  prisms; 
pale  bluish  and  yellowish  green  to  emerald -green,  also  resin  yellow 
and  white,  no  distinct  cleavage. 

ZIRCON,  p.  281.  H.=  7'5;  G.=  4-4'75;  tetragonal,  and  often  in 
square  prisms;  lustre  adamantine;  brown,  gray. 

STAUROLITE,  p.  291.  H.=  7;  G.^3'4-3'8;  in  prisms  of  123°, 
and  often  in  cruciform  twins;  no  distinct  cleavage;  brown,  black, 

tgray. 

QUARTZ,  p.  253.  H.=  7;  G.=  2'6;  often  in  hexagonal  crystals 
with  pyramidal  terminations;  of  various  shades  of  color.  OPAL, 
p.  259,  is  in  part  anhydrous. 


428  DETERMINATION   OF  MINERALS. 

MONAZITE,  p.  222.  H.=  5-5 '5;  G.=  4'9-5'3;  in  small  brown  im- 
bedded monoclinic  crystals,  with  perfect  basal  cleavage;  B.B.  flame 
bluish  green  when  moistened  with  sulph.  acid." 

RUTILE,  p.  179.  H.=  6-6'5;  G.  =  4-15-4'25;  tetragonal;  reddish 
brown  to  brownish  red,  green,  black;  B.B.  reaction  for  titanium. 
BROOKITE  and  OCTAHEDRITE,  p.  180,  are  similar,  except  in  crystal- 
line forms,  and  G.  in  brookite  4'0-4'25,  in  octahedrite  3'8-3'95. 

PEROFSKITE,  p.  180.  H.=  5'5;  G.=  4-4'l;  yellowish,  brown, 
black;  cubic  and  octahedral  forms;  B.B.  reaction  for  titanic  acid. 

ENSTATITE,  p.  264.  H.  =  5'5;  G.  =  3'l-3'3;  in  ortho-rhombic  pris- 
matic and  fibrous  forms  with  I /\  1=  88°  16',  also  foliated;  whitish, 
grayish,  brown,  bronzite  and  hypersthene  contain  iron.  Anihopliyl- 
lite  is  similar,  but  I  /\I=  125°,  and  it  fuses  on  the  edges  with  great 
difficulty. 

lolite,  apatite,  scheelite,  euclase,  fuse  with  much  difficulty,  and  eu- 
clase  gives  some  water  in  closed  tube  when  highly  ignited. 


2.  FUSIBLE  WITH  LITTLE  OR  MUCH  DIFFICULTY. 
A.  Gelatinize  and  afford  a  Stiff  Jelly. 

a.  Hydrous  5  fuse  easily. 

DATOLITE,  p.  311.  H.=  5-5'5;  G.  =  2'8-3;  monoclinic -f  white, 
greenish,  yellowish;  crystals  glassy,  stout,  sometimes  massive  and 
porcellanous,  never  fibrous;  B.B.  fuses  easily,  reaction  for  boron. 

NATROLITE,  p.  321.  H.  =  5-5'5;  G.  =  2'3-2'4;  in  slender  rhombic 
prisms,  and  divergent  columnar;  white,  ywh,  rdh,  red;  B.B.  fuses 
very  easily. 

SCOLECITE,  p.  321.  H.=  5-5'5;  G.=  2'16-2'4;  cryst.  much  like 
natrolite,  but  twinned,  with  converging  stria3  on  i-l  as  in  figure  on 
p.  299;  B.B.  sometimes  curls  up,  fuses  very  easily. 

GMELINITE,  p.  323.  H.  -  4'5;  G.  =  2-2'2;  in  small  and  short  hex- 
agonal or  rhombohedral  cryst. ;  B.B.  fuses  easily. 

PHILIPPSITE,  p.  324.  H.=  4-4'5;  G.=  2'2;  in  twinned  crystals; 
B.B.  fuses  rather  easily. 

LAUMONTITE,  p.  315.  H.  =  3'5-4;  G.=  2'2-2'4;  white,  reddish; 
crystals  become  white  and  crumbling  on  exposure  to  the  air;  B.B. 
fuses  rather  easily. 

Pectolite  (p.  315)  and  Analctte  (p.  322)  imperfectly  gelatinize. 

b.  Hydrous;  fuse  with  much  difficulty. 

CALAMINE,  p.  174.  H.  =  4'5-5:  G.=  3'15-3'19;  white,  greenish, 
bluish;  orthorhombic  in  crystals;  B.B.  fus.  with  great  difficulty,  re- 
action for  zinc  and  none  for  iron;  hydrous. 

SEPIOLITE,  p.  328.  White;  soft  and  almost  clay-like,  also  fibrour, 
B.B.  fuses  with  difficulty,  with  cobalt  solution  reddish;  hydrous. 

PYROSOLERITE,  p.  338.  H.=  3;  G.=  2'74;  micaceous;  B.B. 
fuses  on  thin  edges. 


DETERMINATION   OF   MINERALS.  429 

c.  Anhydrous. 

(X.  NO  REACTION  FOR  SULPHUR;  NO  COATING  ON  COAL. 

NEPHELITE,  p.  293.    H.  =  5'5-6;  G.  =  2'5-2'65;  hexagonal  prisms 

and  massive;  vitreous,  with  greasy  lustre;  white,  ywh,  gyh  brown, 

rdh;  B.B.  fuses  rather  easily. 
WOLLASTONITE,  p. -265.     H.=  45-5;  G.=  2'75-2'9;  white,  gyh, 

rdh,  bnh;  B.B.  fuses  easily. 
SODALITE,  p.  294.     H.  =  5'5-6;  G.  =  213-2'4;  white,  blue,  reddish; 

in  dodecahedrons  and  massive;  B.B.  fuses  not  very  easily. 
WILLEMITE,  p.  173.      H.  =  5'5;  G.  =  3'9-4'3;  white  to  greenish, 

reddish,  brownish;  B.B.  glows  and  fuses  with  difficulty;  reaction 

for  zinc  and  none  for  iron;  anhydrous. 

/?.  REACTION  FOR  SULPHUR  B.B.  WITH  SODA. 

HAUYNITE,  p.  294.  H.=  5'5-6;  G.=  2'4-2'5;  blue,  greenish;  iso- 
metric, in  dodecahedrons,  octahedrons;  B.B.  fuses  with  some  diffi- 
culty. 

DANALITE,  p.  278.  H.  r=  5'5-6;  G.  =  3 '427;  isometric;  flesh-red  to 
gray;  B.B.  fuses  rather  easily,  and  gives  reaction  for  manganese 
and  zinc. 

B.  Not  Gelatinizing. 

1.  STRUCTURE  EMINENTLY  MICACEOUS,  SURFACE  OF  FOLIA 

MORE  OK  LESS  PEARLY;  H.  OF  SURFACE  OF  FOLIA 

NOT  OYEE  3 '5;  ANHYDROUS  OR  HYDROUS. 

MUSCOVITE,  BIOTITE,  PHLOGOPITE,  LEPIDOLITE,  LE- 

PIDOMELANE :  for  distinctions  see  pp.  287-291.  Anhydrous, 
or  affording  very  little  water;  B.B.  fuse  with  difficulty  on  thin 
edges,  excepting  lepidomelane,  which  fuses  rather  more  easily. 

MARGARODITE,  DAMOURITE,  pp.  290,  335.  Much  like  com- 
mon mica,  but  more  pearly  and  greasy  to  the  feel,  folia  not  elastic; 
giving  a  little  water  in  the  closed  tube;  color  usually  whitish. 

PENNINITE,  RIPIDOLITE,  PROCHLORITE,  p.  339.  Usually 
bright  or  deep  green,  blackish  green,  reddish,  rarely  white;  folia 
tough,  inelastic;  B.B.  diff.  fus.,  reaction  for  iron  and  yield  much 
water;  partiallv  decomposed  by  acids. 

VERMICULIT E,  JEFFERISITE,  pp.  338, 339.  Brown,  yellowish 
brown,  green;  exfoliate  remarkably:  yield  much  water. 

MARGARITE,  p.  341.  H.  =  3'5-4'5  (highest  on  edges);  G.  =  2'99; 
white,  ywh,  rdh;  folia  some  what  brittle;  B.B.  fuses  on  thin  edges; 
yields  a  little  water. 

TALC,  p.  326.  H.  =  1-1-5;  G.=  2*5-3 '8;  pearly  and  very  greasy  to 
the  touch;  white  pale  green,  gray;  B.B.  very  difficultly  fusible,  yields 
usually  traces  of  water;  reddish  with  cobalt  solution. 

PYROPHYLLITE,  p.  328.  Similar  to  talc;  but  B.B.  exfoliates  re- 
markably; blue  with  cobalt  solution. 

FAHLUNITE,  p.  336,  has  often  a  more  or  less  distinct  micaceous 
structure. 


430  DETERMINATION   OF   MINERALS. 

Autunite,  p.  188,  has  a  mica-like  basal  cleavage;  but  it  occurs  in 
small  square  tables  of  a  bright  yellow  color.  Diallage,  p.  267,  hus 
a  structure  nearly  micaceous.  Serpentine  is  sometimes  nearly  mi- 
caceous, but  the  folia  are  not  easily  separable  and  are  brittle.  Chlo- 
ritoid  has  a  perfect  basal  cleavage,  but  folia  very  brittle,  and  cleav- 
age less  easily  obtained  than  in  the  preceding;  and  moreover  the 
mineral  is  infusible. 

2.  STRUCTURE  NOT  MICACEOUS. 
a.  Hydrous. 

a.  NO  REACTION  FOE,  PHOSPHORUS,  OR  BORON. 

f  Hardness,  with  the  exception  of  a  variety  of  serpentine,  1  to  3  ; 
lustre  not  at  all  vitreous. 

CHLORITE  S,  p.  337.  H.=  2-2 '5.  Here  fall  the  massive  granular 
chlorites,  olive-green  to  black  in  color,  of  the  species  penninite,  ri- 
pidolite,  prochlwite ;  B.B.  reaction  for  iron,  fuses  with  difficulty; 
yields  much  water. 

VEJRMICUUTE,  p.  338.  H.  =  1-1  "5.  Granular  massive  forms  of 
vermiculite. 

TALC,  p.  336.  H.=  1-1 '5.  Here  falls  steatite  (soapstone)  or  mas- 
sive talc,  of  white  to  grayish  green  and  dark  green  color,  granular 
to  cryptocrystalline  in  texture.  B.B.  fuses  with  great  difficulty, 
and  yields  only  traces  of  water;  no  reaction  for  iron,  or  only  slight. 

PYROPHYLLITE,  p.  328.  Grayish  white,  massive  or  slaty;  B.B. 
like  the  crystallized  in  its  difficult  fusibility  and  little  water  yielded, 
but  does  not  exfoliate. 

SERPENTINE,  p.  329.  H.  =  2-5-4;  G.=  2'36-2'55;  olive-green; 
ywh  green;  blackish  green,  white;  B.B.  fuses  with  difficulty  on 
thin  edges;  yields  much  water. 

FINITE,  p.  334.  H.=  25-3'5;  G.=  2'6-2'85;  lustre  feebly  waxy; 
gray,  gnh,  bnh.  B.B.  fuses;  yields  water. 

DAMOURITE,  p.  335.  Same  as  crystallized,  p.  403,  but  in  massive 
aggregation  of  scales.  _ 

ft  Hardness  3-5  to  6-5 ;  lustre  often  pearly  on  a  cleavage  surface, 
but  elsewhere  vitreous. 

PREHNITE,  p.  317.     H.=  6-6'5;  G.=  2'8-3;  pale  green  to  white; 

crystals  often  barrel-shaped,  made  of  grouped  tables;  B.B.  fuses 

very  easily;  decomp.  by  HC1. 
FECTOLITE,  p.   315.     H  =  5  ;  G.=  2'68-2'8;  white;  divergent 

fibrous,  or  acicular;  B.B.  fuses  very  easily;  gelatinizes  imperfectly 

with  HC1. 
APOFHYLLITE,  p.  316.    H.  =  4'5-5;  G.  =  2'3-2'4;  white,  gnh,  ywh, 

rdh;  tetragonal,  one  perfect  pearly  cleavage  transverse  to  prism; 

B.B. fuses  very  easily;  a  fluorine  reaction;  decorap.  by  HC1. 
CHABAZITE,  p.  322.   H.  =  4-5;  G.  =  2-2 "2;  rhombohedral,  vitreous; 

White,  rdh;  B.B.  fuses  easily;  decomp.  by  HC1. 
HARMOTOME,  p.   323.     H.  =  4'5;   G.=  244;  white,   ywh,   rdh; 

crystals  twins,  usually  cruciform;  B.B.  fuses  not  very  easily;  vitre- 
ous in  lustre;  decomp.  by  HC1. 
STILBITE,  p.  324.    H.  =  3'5-4;  G.  =  2-2-2;  white,  ywh,  red;  crystal- 


DETERMINATION  OF  MINERALS.          431 

lizatipns  often  radiated-lamellar;  one  perfect  pearly  cleavage;  B.B. 

exfoliates,  fuses  easily;  decomp.  by  HC1. 
HEULANDITE,  p.  325.     H.=  3'5-4;  G.=  2'2;  in  oblique  crystals, 

with  one  perfect  pearly  cleavage;  B.B.  same  as  for  stilbite 
EUCIiASE,  p.  311.     H.  =  7-5;  G.  —  3*1;  in  glassy  transparent  mofio- 

clinic  crystals;  B.B.  fuses  -with  great  difficulty;  gives  water  in  closed 

tube  when  strongly  ignited. 

Prehnite,  apophyllite,  chdbazite,  harmotome,  heulandite,  and  eudase 
never  occur  in  fibrous  forms.  Epidote  and  zoisite  (p.  407),  like  euclasc, 
give  out  water  when  strongly  ignited. 

ft  REACTION  EITHER  FOR  PHOSPHORUS  OR  BORON. 

VIVIANITE,  p.  203.  H.=  l'5-2;  G.  =  2 '55-7;  monoclinic  with  one 
perfect  cleavage;  white,  blue,  green;  B.B.  fuses  very  easily,  the  flame 
bluish  green,  a  gray  magnetic  globule;  in  HC1  sol. 

ULEXITE,  p.  231.  H.  =  1;  G.  =  1'65;  white,  silky,  in  fine  fibres; 
B.B.  fuses  very  easily,  and  moistened  with  sulph.  acid  flame  for  an 
instant  green,  owing  to  the  boron  present;  little  sol.  in  hot  water. 
PRICEITE  (p.  212)  is  in  texture  and  color  like  chalk;  similar  to 
ulexite  in  green  flame  B.B. 

Borax  and  Sassolite  are  other  .soft  minerals  containing  boron,  but 
these  have  taste. 

b.  Anhydrous. 
a.  B.B.  the  flame  lithium-red. 

SFODUMENE,  p.  269.  H  =  6'5-7;  G.  =  3-13-3'19;  white,  gyh,  gnh 
white,  reddish,  emerald-green,  monoclinic  (like  pyroxene),  with 
I A  1=  87°,  and  perfect  cleavage  parallel  to  /and  i-i;  B.B.  swells 
and  fuses. 

PETALITE,  p.  269.  H.  =  6-6'5;  G.  =  2 '4-2-5;  white,  gray;  rdh, 
gnh;  B.B.  becomes  glassy  and  fuses  only  on  the  edges. 

AMBLYGONITE,  p.  218.  H.  =  6  ;  G.  =  3-31  ;  mountain  green, 
gyh,  white,  bnh;  B.B.  fuses  very  easily,  reaction  for  fluorine. 

TRIPHYLITE,  p.  208.  H.  =  5;  G.  =  3'5-3'6;  greenish  gray,  bluish, 
often  bnh  black  externally;  B.B.  fuses  very  easily,  globule  mag- 
netic; with  soda,  manganese  reaction. 

LEPIDOLITE,  p.  289.  H.  =  2  5-4  ;  G.  =  2 '8-3  ;  micaceous,  also 
scaly-granular;  rose-red,  pale  violet,  white,  gyh;  B.B.  fuses  easily: 
after  fusion  gclat.  with  HC1.  Some  biotite,  p.  291,  gives  the  lithia 
reaction. 

/?.  B.B.  boron  reaction  (green  flame). 

TOURMALINE,  p.   304.     H.  =  7  ;  G.  =  2'9-3'3  ;   rhombohedral, 

prisms  with  3,  6,  9  sides,  no  longitudinal  or  other  distinct  cleavage; 

black,  blue  black,  green,  red,  rarely  white ;   lustre  of  dark  var. 

resinous;  B.B.  fusion  easy  for  dark  var.  and  diff.  for  light. 
AXINITE,  p.  286.     H.  =*6'5-7  ;  G.  =  3'27  ;  triclinic.  sharp-edged, 

glassy  crystals;  rich  brown  to  pale  brown  and  grayish,  B.B.  fuses 

readily;  with  borax  violet  bead. 
BORAOITE,  p.  225.     H.  =  7  ;  G.  =  2 '97  ;  isometric  ;  white,  gyh, 

gnh;  lustre  vitreous;  fuses  easily,  coloring  flame  green. 

Dariburite,  p.  286,  is  another  boron  silicate. 


432  DETERMINATION   OF  MINERALS. 

y.  Reaction  for  titanium. 

TITANITE,  p.  312.  H.  =  5-55;  G.  =  3'4-3'56;  monoclinic;  usually 
in  thin  sharp-edged  crystals ;  brown,  ywh,  pale  green,  black ; 
lustre  usually  subresinous;  B.B.  fuses  with  intumescence. 

6".  Reaction  for  fluorine  or  phosphorus. 

CRYOLITE,  p.  216.  H.  =  2'5;  G.  =  2'9-3;  white,  rdh,  bnh;  fuses 
in  the  flame  of  a  candle;  soluble  in  sulph.  acid  which  drives  off 
hydrogen  fluoride,  a  gas  that  corrodes  glass. 

FLUORITE,  p.  227.  H.  =  4;  G.  =  3-3'25;  isometric,  with  perfect 
octahedral  cleavage,  and  massive:  white,  wine-yellow,  green,  pur- 
ple, rose-red,  and  other  bright  tints;  phosphoresces;  when  heated, 
decrepitates ;  B.B.  fuses,  coloring  the  flame  red ;  after  ignition, 
alkaline. 
Lepidolite  (p.  289),  Amblygonite  (p.  218),  give  a  fluorine  reaction. 

APATITE,  p.  232.  H.  =  4'5-5;  G.  =  2'9-3'25;  often  in  hexagonal 
prisms;  pale  green,  bluish,  yellow,  rdh,  bnh,  pale  violet,  white; 
B.B.  fuses  with  difficulty,  moistened  with  sulph.  acid  and  heated, 
flame  bluish  green  from  presence  of  phosphorus;  sometimes  reaction 
for  fluorine. 

e.  Reaction  for  iron. 

GARNET,  p.  278.  H.  =  6'5-7'5;  G.  =  3'15-4-3;  isometric,  usually 
in  dodecahedrons  and  trapezohedrons,  also  massive,  never  fibrous  or 
columnar;  red,  bnh  red,  black,  cinnamon-red,  pale  green  to  emerald- 
green,  white.  B.B.  dark- colored  varieties  fuse  easily,  and  give 
iron  reaction,  but  emerald -green  var.  almost  infusible;  a  white  to 
yellow  massive  garnet  is  hardly  determinable  without  chemical 
analysis. 

VESUVIANITE  (Idocrase),  p.  282.  H.  =  6 '5  ;  G.  =  3 '35-3 '45  ; 
tetragonal  and  often  in  prisms  of  four  or  eight  sides,  never  fibrous; 
brown  to  pale  green,  ywh,  bk;  B.B.  fuses  more  easily  than  garnet; 
reaction  for  iron. 

EPIDOTE,  p.  283.  H.  =  6-7;  G.  =  3'25-3-5;  in  monoclinic  cryst. 
and  massive,  rarely  fibrous;  unlike  amphibole  in  having  but  one 
cleavage  direction;  ywh  green,  bnh  green,  black,  rdh,  yellow,  dark 
gray  ;  B.B.  fuses  with  intumescence  ;  contains  some  water,  but 
separated  only  at  a  high  temperature. 

AMPHIBOLE,  dark  varieties  including  hornblende,  actinolite,  and 
other  green  to  gray  and  black  kinds,  p.  270.  H.  =  5*6;  G.  =  3-3-4-, 
monoclinic,  in  short  or  long  prisms,  often  long  fibrous,  lamellar,  and 
massive,  prisms  usually  four  or  six  sides,  I  A  /=  124^°,  cleavage 
par.  to  /;  B.B.  fusion  easy  to  moderately  difficult. 

ANTHOPHYLLITE,  p.  273,  like  hornblende,  but  orthorhombic ; 
bnh  gray  to  bnh  green,  sometimes  lustre  metalloidal;  B.B.  fuses 
with  great  difficulty. 

PYROXENE,  augite,  and  all  green  to  black  varieties,  p.  265.  H.  = 
5-6;  G.  =  3 '2-3  5;  monoclinic,  in  short  or  oblong  prisms,  lamellar, 
columnar,  not  often  long,  fibrous  or  asbestiform,  prisms  usually 
with  four  or  eight  sides,  I/\I=  87°  5',  cleavage  par.  to  /;  B.B.  as 
in  hornblende. 


DETERMINATION   OF   MINERALS.  433 

HYPERSTHENE,  p.  264.  H.  =  5-6;  G.  =  3'39;  cryst,  nearly  as  in 
pyroxene,  but  orthorhombic,  usually  foliated  massive,  also  fibrous  ; 
bnh  green,  gyh  black,  pinchbeck -brown;  B.B.  fuses  with  more  or 
less  difficulty.  Bronzite,  p.  244,  is  similar  and  almost  infusible. 

IOLITE,  p.  287.     H.  =  7-7 "5  ,  G.  =  ,2 "6-2 '7  ;  orthorhombic;  blue  to 
blue  violet ;  looks  like  violet-blue  glass ;  B.B.  fuses  with  much 
difficulty. 
Tourmaline,  much  Titanite,  and  Ilvaite  (p.  285),  B.B    give  iron 

reaction. 

£.  No  reaction  for  iron. 

SCHEELITE,  p.  232.  H.  =  4'5-5;  G.  =  5'9-6'l;  tetragonal;  ywh, 
gnh,  rdh,  pale  yellow ;  lustre  vitreous-adamantine ;  fuses  on  the 
edges  with  great  difficulty. 

SCAFOLITES,  p.  292.  H.  =  55-6;  G.  =  2'6-2'74;  tetragonal,  often 
in  square  prisms ;  white,  gray,  gnh  gray ;  B.B.  fuses  easily  with 
intumescence. 

ZOISITE,  p.  285.  H.  =  6-65;  G.  =  3  l-3'4;  orthorhombic,  oblong 
prisms  and  lamellar  massive,  cleavage  in  onty  one  direction  ;  like 
epidote  in  giving  out  some  water  when  highly  ignited. 

AMFHIBOLE,  white  var.  (tremolite),  p.  270.  Same  as  for  other 
amphibole  (above),  except  in  color;  B.B.  fuses. 

PYROXENE,  white  var. ,  p.  266.  Same  as  for  other  pyroxene  (above), 
except  in  color;  B.B.  fuses. 

ORTHOCLASE,  p.  300.  H.  -  6-6'5  ;  G.  =  2'4-2'62  ;  monoclinic, 
stout  cryst.,  and  massive,  never  columnar,  two  unequal  cleavages, 
the  planes  at  right  angles  with  one  another,  and  cleavage  surfaces 
never  finely  striated,  as  seen  under  a  pocket  lens  or  microscope; 
white,  gray,  flesh-red,  bluish,  green;  B.B.  fuses  with  some  difficulty. 

ALBITE,  p.  299,  OLIGpCLASE,  p.  299  H.  =  6;  G.  =  2'56-2'72, 
triclinic,  but  cryst.  as  in  orthoclase,  except  that  the  two  cleavage 
planes  make  an  angle  of  93£°  to  94°,  and  one  of  them  has  the  surface 
striated ;  white  usually,  flesh-red,  bluish ;  B.B.  fuse  with  a  little 
difficulty;  not  acted  on  by  acids. 

LABRADORITE,  p.  298.  H.  =  6  ;  G.  =  2'66-2-76;  tricliuic,  like 
albite  in  cryst ,  and  nearly  in  cleavage  angle,  93°  20',  and  in  striae 
of  surface;  white,  flesh-red,  bnh  red,  dark  gray,  gyh  brown;  B.B. 
fuses  easily;  decomposed  by  HC1  with  difficulty. 

ANORTHITE,  p.  298.  H.  =  6-7;  G.  =  2'66-2'78;  cryst.  and  striae 
as  in  albite,  cleavage  angle  94°  10';  white,  gyh,  rdh;  B.B.  fusion 
difficult;  decomposed  by  HC1  with  separation  of  gelat.  silica 

MICROCLINE,  p.  300.  Very  near  orthoclase  in  all  characters,  but 
triclinic,  cleavage  angle  differing  only  16'  from  a  right  angle,  and 
surface  of  most  perfect  cleavage  striated,  but  striae  exceedingly 
fine,  often  difficult  to  detect  with  a  good  pocket  lens,  and  requiring 
the  aid  of  a  polariscope;  color  white,  gray,  flesh-red,  often  green. 
For  optical  distinctions  of  FELDSPARS,  see  beyond 

EUCLASE,  p.  311.  H.  =  7'5  ;  G.  =  3'1 ;  in  monoclinic  crystals, 
with  one  perfect  diagonal  cleavage  ,  pale  green  to  white,  bnh ; 
transparent;  becomes  electric  by  friction. 


ON  KOCKS.-PETROLOGY. 


THE  term  Petrology,  signifying  the  science  of  Rocks,  em- 
braces the  study  of  the  origin  and  transformation  of  rocks, 
as  well  as  their  classification  and  distinctive  characters. 
The  last  of  these  subjects  alone  is  included  under  the  term 
Petrography. 

Rocks  are  made  up  of  minerals.  A  few  kinds  consist  of 
a  single  mineral  alone  :  as,  for  example,  limestone,  which 
may  be  either  the  species  calcite  or  dolomite ;  quart zyte 
(along  with  much  sandstone),  which  is  quartz  ;  and  felsyte, 
which  is  orthoclase.  But  even  these  simple  kinds  are  sel- 
dom free  from  other  ingredients,  and  often  contain  visibly 
other  minerals.  Nearly  all  kinds  of  rocks  are  combinations 
of  two  or  more  minerals.  They  are  not  definite  compounds, 
but  indefinite  mixtures,  and  hardly  less  indefinite  than  the 
mud  of  a  mud-flat.  The  limits  between  kinds  of  rocks 
are  consequently  ill-defined.  Granite  graduates  insensibly 
into  gneiss,  and  gneiss  as  insensibly  into  mica  schist  and 
quartzyte,  syenyte  into  granite,  mica  schist  into  hornblende 
schist,  granite  also  into  a  compact  porphyry-like  rock,  and 
quartz-trachyte  ;  and  so  it  is  with  many  other  kinds.  The 
fact  is  a  chief  source  of  the  difficulty  in  studying  and  de- 
fining rocks,  and  especially  the  crystalline  kinds.  The 
different  rocks  are  not  species  in  the  sense  in  which  this 
word  is  used  in  science,  but  only  kinds  of  rocks. 

I.  CONSTITUENTS  OF  ROCKS. 

The  following  is  a  list  of  the  chief  constituent  minerals 
and  of  the  more  important  of  the  accessory  species : 

A.  SILICEOUS  SPECIES  A:NT>  SILICATES. 

1.  Quartz,  tridymite,  opal. 

2.  The  FELDSPARS  :  all  NON-FERRIFEROUS  ;  all  ALKALINE  (alkali- 
bearing,  containing  either  potash  or  soda)  except  anorthite;  orthoclase, 


CONSTITUENTS   OF    ROCKS.  435 

microcline,  oligoclase,  labradwite,  the  more  abundant ;  andesine,  anor- 
thite,  albite,  and  intermediate  kinds,  less  so. 

3.  OTHER  NON-FERRIFEROUS  ALKALINE  MINERALS:  leucite,  con- 
taining 17  to  21  p.  c.  of  potash,  with  the  atomic  ratio  that  of  andesine; 
nephslite  (elseolite),  15  to  16  p.  c.  of  soda  with  5  or  6  of  potash ;  soda- 
lite,  20  to  25  p.  c.  of  soda  ;  some  scapolites,  5  to  6  p.  c.  of  soda;  spodu- 
mene,  about  5  p.  c.  of  lithia. 

4.  OTHER  NON-FERRIFEROUS  ALKALINE  MINERALS:  THE  SAUSSUR- 
ITE-ZOISITE  GROUP:  light-colored,  tough,  jade-like  minerals,  derived 
(as  shown  by  remains  of  crystalline  forms  and  cleavage)  from  the 
alteration  mainly  of  labradorite  or  anorthite,  and  in  the  change  becom- 
ing of  high  specific  gravity  (3-3'4);  contain  4  to  5  p.  c.  of  alkali, 
nearly  all  of  it  soda,  and  40  to  50  p.  c.  of  silica.     See  on  Saussurite, 
p.  285. 

5.  The  MICAS:  ALKALINE,  AND  CONTAINING  MORE  OR  LESS  IRON. 
Biotite  is  often  styled  magnesia-mica,  although  truly  a  potash  mica 
like  muscovite.     Some  muscovite,  biotite,  and  other  species  contain 
lithia  as  well  as  potash.     Gieseckite  or  pinite  has  the  composition  of  a 
hydrous  mica,  but  occurs  only  massive,  and  usually  as  a  pseudomorph. 

6.  ALKALINE  FERRIFEROUS  SPECIES:  Acmite  and  cegirite,  near  py- 
roxene in  angle,  10  to  13  p.  c.  of  soda;  arfvedsonite  and  glaucophane, 
near  hornblende,  5  to  9  p.  c.  of  soda.     A  few  analyses  of  ordinary 
hornblende  give  1  to  4  p.  c.  of  soda. 

7.  NON- ALKALINE  FERRIFEROUS  SPECIES:  part  of  amphibole  (horn- 
blende, srnaragdite),  pyroxene  (augite,  diallage,  etc.)  and  garnet,  with 
hypersthene,  epidote,  tourmaline,  chrysolite,  staurolite. 

8.  NON- ALKALINE,  NON-FERRIFEROUS  SPECIES  :  enstatite  (in  part), 
cyanite,  andalusite,  fibrolite  (sillirnanite). 

9.  HYDROUS  NON-ALKALINE  SPECIES  :  serpentine,  talc,  pyrophyllite, 
chlorite ;  the  first  two  magnesian,  without  iron  or  aluminium,  ex- 
cept as  impurity  ;  the  third,  aluminous  and  talc-like,  without  iron  or 
magnesium;  the  fourth,  containing  iron,  mangesium,  and  aluminium. 

Of  these  silicates,  tourmaline  is  peculiar  in  containing  5  to  9  p.  c. 
of  boron. 

B.  CALCAREOUS,  OR  CARBONATES,  SULPHATES,  AND  PHOS- 
PHATES OF  LIME. 

Cakite,  dolomite,  arngonite,  gypsum,  anhydrite,  apatite. — Aragpniteis 
a  large  constituent  of  common  uncrystalline  limestones,  for  this  form 
of  calcium,  carbonate  enters  into  the  constitution  of  many  shells  and 
some  otb.er  organic  secretions,  out  of  which  limestones  have  to  a  great 
extent  been  made.  Apatite,  or  calcium  phosphate,  occurs  in  beds  and 
veins  in  large  crystallizations ;  but  is  of  especial  interest  petrologically 
because  distributed  sparingly  in  microscopic  crystals  through  most 
igneous  and  metamorphic  rocks. 

C.  IRON  OXIDES  AND  SULPHIDES. 

Hematite,  magnetite,  mennccanite,  pyrite,  pyrrhotite,  marcasite. — The 
oxides  constitute  beds  ;  in  microscopic  grains  all  are  very  common  in 
basic  igneous  rocks  and  in  many  metamorphic  rocks. 


436  DESCRIPTIONS  OF  ROCKS. 

Of  the  above-named  silicates  the  prominent  constituents 
of  the  common  rocks  include  about  twenty.  These  are : 
orthodase,  microdine,  oligoclase,  andesine,  labradorife, 
anorthite,  muscovile,  biotite,  hydrous  micas;  nephelite 
(the  massive  form  of  which  is  called  dceolite),  leucite;  horn- 
blende, pyroxene  (augite),  hyperslliene ;  chrysolite,  serpen- 
tine, and  two  or  three  species  of  chlorite. 

a.  Arrangement  of  the  enumerated  species  according  to 
the  proportion  of  silica,  or  the  acidic  constituent,  in  the 
mineral. 

1.  The   emin-sntly  acidic   species.     Orthoclase    (having 
about  65  p.  c.  of  silica),  albite  (about  67),  oligoclase  (about 
60),  spodumene  (about  64),  talc  (about  62). 

2.  Sub-acidic  species.     Andesine  (about  58  p.  c.),  leu- 
cite  (about  56),  dipyre  among  scapolites  (about  56),  glau- 
cophane  (55-58). 

3.  Basic  species.      Labradorite   (mostly  50-54  p.    c.), 
anorthite  (about  44),  nephelite  (about  44),  most  scapolite 
with  meionite  (40-47),  the  micas  (mostly  40  to  49),  gie- 
seckite  (45-48)  ;  saussurites  (40-50),  zoisite  (mostly  40-42) ; 
hornblende  of  black  and  dark  colors  (mostly  40-50,  but  the 
light  green  and  white  var.,  55-60),  arfvedsonite  (49-51), 
pyroxene  of  black  or  dark  colors  (mostly  44-52,  diallage 
49-52,  but  light  green  and  whitish  pyroxene  52-56)  ;  hy- 
persthene  (50-53,  but  enstatite  54-57),  segirite  (50-52,  but 
acmite  51-55) ;  serpentine  (mostly  41-43  p.  c.). 

4.  Ultra-basic  species.     Sodalite  (with  haiiynite  about 
37  p.  c.),  epidote  (mostly  36-38),  zircon  (32-34),  garnet 
(34-40),    chrysolite   (mostly  36-40,   but  fayalite   29-30), 
tourmaline   (mostly  36-40),   andalusite   (36-40),   fibrolite 
(36-40),  cyanite  (36-40),  topaz  (mostly  33-35),  staurolite 
(about  30),  chlorite  (mostly  25-34),  chloritoid  (ottrelite) 
(23-27  p.  c.). 

b.  The  distinction  of  acidic  and  basic  is  one  easily  used 
in  the  subdivision  of  rocks,  but  it  is  not  necessarily  that  of 
greatest  value  as  regards  the  nature  and  origin  of  rocks. 
That  connected  with  the  kind  of  base  is  in  many  cases  more 
fundamental,  and  its  use  in  conjunction  with  the  former  is 
to  some  extent  required.     The  two  influential  groups  in 
this  respect  are  :  the  alkaline,  characterized  by  the  presence 
of  potash  and  soda  ;  and  the  ferriferous,  having  much  iron 
and  little  or  no  alkali ;  the  former  low  in  specific  gravity 
(mostly  under  2*75),  the  latter  high  (over  2 -75).     Using 


DISTINCTIONS   AMOXG    ROCKS.  437 

this  characteristic,  sodalite  and  nephelite  may  have  a  place 
with  the  potash  and  soda  feldspars,  where  they  belong; 
and  the  micas  also,  because  of  their  potash. 

The  acidic  character  of  a  rock  is  enhanced  by  the  pres- 
ence of  quartz  (free  silica).  But  the  amount  of  quartz 
which  may  occur  in  any  quartz-bearing  rock  varies  from 
very  little  to  much  ;  and  the  same  mineral  constitution 
often  occurs  without  quartz.  Thus  syenyte  (hornblende 
and  orthoclase),  dioryte  (hornblende  and  oligoclase),  fel- 
syte  (orthoclase),  trachyte  (orthoclase),  amphiboly te  (horn- 
blende), granite  (orthoclase  and  mica),  gabbro  and  diabase 
(augite  and  labradorite),  etc.,  occur  with  and  without 
quartz.  Quartz  is  thrown  about  freely  among  eruptive 
as  well  as  metamorphic  and  fragmental  rocks,  and  its  pres- 
ence or  not  is  a  characteristic  therefore  of  inferior  value, 
although  of  geological  interest.  It  is  absent  from  augitic 
rocks  more  commonly  than  from  hornblendic. 

c.  The  par  amor pliic  relations  of  certain  of  the  mineral 
species,  explained  on  page  61,  have  an  important  bearing 
on  the  relations  and  origin  of  some  rocks.  The  difference 
in  crystallization  in  paramorphs — for  example,  in  pyroxene 
and  hornblende— is  an  unstable  difference,  one  of  the  two 
species  lapsing  readily,  under  certain  conditions,  into  the 
other.  Through  paramorphism,  therefore,  two  rocks  may 
be  different  mineralogically  while  identical  chemically,  and 
by  easy  alteration  become  identical  mineralogically. 

The  cases  of  paramorphism  of  greatest  importance  petro- 
logically  are  the  following :  that  of  pyroxene  and  norn- 
blende,  of  Jiypersthene  and  hornblende,  and  of  aragonite  and 
calcite ;  and,  besides  these,  there  are  that  of  andalusite  and 
cyanite,  of  tridymite  and  quartz,  of  opal  and  quartz,  of 
glass  and  stone.  The  name  of  the  least  stable  species  in 
each  case  is  here  italicized.  Further  remarks  on  the  altera- 
tions are  made  and  illustrated  beyond. 

II.   DISTINCTIONS  AMONG  ROCKS. 
1.  Based  on  General  Methods  of  Origin. 

The  first  and  most  obvious  division  among  rocks  is 
into  (1)  Uncrystalline  and  (2)  Crystalline. 

Uncrystalline  rocks  are  made  of  the  fragments  of  older 
rocks — that  is,  out  of  the  sand,  mud,  clay,  gravel,  derived 


438  DESCRIPTIONS  OF   ROCKS. 

from  them  through  disintegration  and  decomposition;  and 
they  represent,  but  in  a  consolidated  form,  the  sand-beds, 
gravel-beds,  and  mud-deposits  of  past  time.  They  include 
also  the  limestones,  which  were  made  from  the  ground 
shells,  corals,  etc.,  of  the  same  eras.  They  are  therefore 
called  Fragmental  rocks;  or,  using  a  corresponding  word 
adopted  from  the  Greek  (Iclastos,  broken),  Clastic  rocks. 

Crystalline  rocks  are  made  not  of  worn  or  broken  grains 
like  fragmental  rocks,  but  of  crystalline,  as  in  marble  and 
granite.  There  are  three  divisions  of  them  :  (1)  igneous  or 
eruptive,  or  those  rocks  which  came  up  melted  from  depths 
below  through  fissures  or  through  volcanic  vents ;  (2)  meta- 
morphic  rocks,  or  those  that  were  made  by  metamorphism 
out  of  common  limestones,  common  fragmental  rocks,  or  out 
of  older  crystalline  rocks  ;  (3)  chemically  deposited,  made  by 
deposition  from  solution,  like  travertine  (p.  236)  from  cal- 
careous waters,  and  like  the  siliceous  deposits  from  the 
geyser  waters  of  Iceland,  or  of  Yellowstone  Park,  etc. 

Among  eruptive  and  metamorphic  crystalline  rocks  other 
distinctions  are  used,  as  follows. 

2.  Based  on  Mineral  Constitution. 

This  is  the  criterion  of  chief  importance.  If  a  rock  con- 
sists of  two  or  more  minerals,  the  two  most  characteristic 
are  usually  taken  as  the  essential  constituents,  and  the 
others  are  regarded  as  qualifying  minerals  distinguishing 
varieties,  or  else  as  accessory  species.  Quartz,  because  of 
its  so  universal  distribution  among  rocks,  is  one  of  the  less 
important  ingredients,  as  observed  above;  it  is  the  basis 
of  quartz-bearing  and  quartzless  kinds  under  most  of  the 
eruptive  and  metamorphic  rocks. 

In  granite  (consisting  of  quartz,  feldspar,  and  mica), 
with  its  schistose  variety,  gnaiss,  the  most  strongly  pro- 
nounced characteristic  proceeds  from  the  two  potash-bear- 
ing constituents ;  it  is  the  chief  potash-bearing  rock  in  the 
world's  foundations.  The  second  marked  feature  of  gran- 
ite is  the  "  acidic"  quality  of  the  feldspar,  orthoclase.  The 
quartz  serves  only  to  heighten  the  acidic  quality  of  the 
rock  :  it  may  be  absent  altogether,  without  aifecting  essen- 
tially its  chemical  or  mineral  nature.  So  it  is  in  felsyte, 
syenyte,  which  are  also  among  the  acidic  rocks  :  the  quartz 
is  the  less  essential  and  varying  ingredient.  Quartz  occurs 


DISTINCTIONS   AMONG   ROCKS.  439 

occasionally  among  some  basic  labradorite  rocks,  but  they 
are  nevertheless  basic  rocks. 

3.  Based  on  Variations  in  Crystalline  Condition  or 

Texture. 

The  distinctions  based  on  crystalline  condition  or  texture 
speak  strongly  to  the  eye,  and  were  formerly  deemed  of 
prominent  importance. 

a.  Foliated  or  not. — This  distinction  has  reference  to  the 
species  hornblende  and  pyroxene.     The  foliated  variety  in 
each  (called  smaragdite  in  the  former  and  diallage  in  the 
latter)  has  no  chemical  and   small  mineralogical   impor- 
tance, and  recently  it  has  been  proved  by  Judd  that  it  is 
usually  a  result  of  slight  or  incipient  alteration. 

b.  Fine-grained  or  not. — The  rocks  granulyte,  quartz- 
felsyte,  and  rhyolyte  have  essentially  the  same  mineral 
composition,  but  differ  in  texture;  and  so  also  trachyte 
and  the  felsyte  that  is  free  from  quartz ;  dioryte  and  an- 
desyte  ;  quartz-dioryte  and  dacyte ;  gabbro,  diabase,  doler- 
yte,  and  basalt.     The  use  of  different  names  in  such  cases 
is  often  convenient,  but  the  fundamental  identity  should 
not  be  overlooked.     Degree  of  fineness  or  coarseness  has 
depended  chiefly  on  rate  of  cooling,  the  finer  kinds  result- 
ing from  relatively  rapid  cooling.     The  eruptive  rock  fill- 
ing a  large  fissure,  or  a  space  opened  between  layers  of  a 
stratified  rock,  is  often  aphanitic  in  its   outer  portion, 
where  it  was  rapidly  cooled  against  cold  walls,  while  coarse- 
grained within,  where  cooling  was  very  slow.     The  same 
igneous  mass  has  been  found  to  be  scoriaceous  and  apha- 
nitic exteriorly,  while  granite-like  inside,  with  gradations 
between:  as  in  Nevada,  where  the  Sutro  tunnel  gives  a 
complete  section  four  miles  long  (Hague  &  Iddings,  1885) ; 
in  Ireland,  where  the  rock  of  the  same  mass  varies  from 
euphotide  having  a  granitoid  texture  in  part,  through 
diabase  and  doleryte  to  scoriaceous  basalt  and  basalt-glass 
(J.  W.  Judd,  1885) ;  in  Italy,  where  other  examples  occur 
of  the  same  transition  from  coarse  and  compact  euphotide 
to  basalt  and  basaltic  glass  (B.  Lotti,  1886). 

The  cellules  and  scoriaceous  character  of  an  eruptive 
rock  are  due  to  the  expansive  action  of  suddenly  produced 
vapor  :  the  vapor  usually  of  water  ;  but  sometimes  of  car- 
bonic acid,  or  other  vaporizable  material.  It  is  absent, 
therefore,  at  depths  below,  where  the  pressure  was  too  great 


440 


DESCRIPTIONS   OF   ROCKS. 


to  allow  of  vaporization.  The  cavities  of  an  amygdaloid  are 
similar  in  origin  to  those  of  a  scoria.  In  the  trap  of  the 
Connecticut  valley  these  cavities  are  sometimes  cylindrical, 
the  diameter  not  greater  than  that  of  a  pipe-stem,  while 
two  or  three  inches  long;  they  were  made  (the  author 
deems  probable)  by  the  sudden  vaporization  of  minute 
drops  of  liquid  carbonic  acid. 

c.  Porphyritic  or  not. — When  a  constituent  mineral  is 
in  defined  crystals,  and  especially  when  that  mineral  is  a 
feldspar,  the  rock  is  said  to  be  porpliyritic  (Figs.  1  to  3). 
The  ground-mass  or  base  may  be  either  fine  or  coarse  in 
texture.  The  porphyry  of  the  ancients  has  an  aphanitic 
ground-mass,  with  thickly  sprinkled  feldspar  crystals  of 
lighter  color.  Fig.  1  represents  the  red  antique  porphyry 
of  Egypt — now  called  Rosso  antico — the  rock  which  gave 
the  name  porphyry  to  geology,  a  kind  much  used  by  the 


Rosso  Antico.         Oriental  Verd-antique.        Porphyritic  gneiss. 


Romans  (though  not  by  the  Greeks  or  Egyptians),  and 
quarried  by  them  in  the  mountain  Djebel-Dokhan,  twenty- 
five  miles  from  the  Red  Sea,  in  latitude  27°  20'.  Figure  2 
is  from  a  polished  piece  of  green  antique  porphyry  from 
western  Greece.  The  feldspar  crystals  are  comparatively 
large,  and  the  compact  base  has  a  dark  green  color. 
Figure  3  represents  a  large  crystal  of  orthoclase  in  gneiss, 
from  a  porpliyritic  gneiss.  The  feldspar  crystals  in  porphy- 
ritic  gneiss  or  granite  are  sometimes  over  three  inches  long. 


DISTINCTIONS  AMONG   ROCKS.  441 

The  orthoclase  crystal  in  porphyritic  rocks  is  often  a  Carls- 
bad twin  (p.  301),  the  plane  of  cleavage  of  one  half  making 
an  angle  of  52°  23'  with  that  of  the  other  half  (Fig.  3). 

Rocks  are  also  said  to  be  porphyritic  when  they  contain 
augite  (pyroxene),  or  quartz,  or  some  other  mineral  dis- 
seminated through  the  mass  in  denned  crystals ;  and  the 
terms  orthopliyre,  augitophyre,  quartzopliyre,  and  others 
similar  in  form,  have  thus  originated.  As  various  kinds  of 
rocks  may  thus  be  orthophyres,  etc.,  precision  in  describ- 
ing them  is  obtained  by  making  the  word  an  adjective,  and 
indicating,  in  each  case,  the  kind  of  mineral  that  is  por- 
phyritically  defined:  thus,  avgitophyric,  when  the  mineral  is 
augite;  quart zopliyric,  when  quartz;  chrysophyric,  when 
chrysolite ;  leucitophyric,  when  leucite ;  ortliophyric,  when 
orthoclase ;  oligophyric,  when  oligoclase ;  lalradophyric, 
when  labradorite;  anorthophyric,  when  anorthite;  and 
so  on. 

Porphyritic  rocks  are  often  treated  in  petrology  as  if  porphyry  were 
a  distinct  kind  of  rock,  or  as  if  the  porphyritic  variety  of  a  kind  of 
rock  merited  special  prominence.  But,  as  recognized  beyond,  "fel- 
syte-porphyry"  is  porphyritic  felsyte  ;  "  dioryte  porphyry"  is  porphy- 
ritic dioryte;  "  diabase-porphyry"  is  porphyritic  diabase;  and,  in  these 
and  other  like  cases,  the  heing  porphyritic  is  a  characteristic  of  minor 
value.  On  the  other  hand,  a  quarts  porphyry,  as  the  term  has  been 
used,  is  not,  consistently  with  the  other  kinds,  porphyritic  quartzyte; 
but,  inconsistently,  almost  any  rock  except  quartzyte,  which  contains 
disseminated  quartz  in  defined  crystals  or  grains  ;  the  name  is  doubly 
objectionable  because,  besides  the  above  inconsistency,  it  covers  rocks 
of  various  mineral  constitution. 

d.  Glass  and  Stone;  Microlites. — Besides  the  distinction 
of  coarse  and  fine  in  texture  among  eruptive  rocks,  there  is 
also  that  of  glass  and  stone.  All  stages  in  the  gradation 
from  stone  to  glass  exist,  and  few  modern  igneous  rocks, 
and  not  all  of  the  ancient,  however  stony  they  may  appear 
to  the  eye,  are  wholly  stone,  or  holocrystalline,  as  they  are 
then  termed  (from  the  Greek  holos,  all,  and  crystalline). 
Glass  is  stony  material  that  has  been  somewhat  rapidly 
cooled  from  fusion  ;  it  is  most  common  in  connection  with 
orthoclase  lavas.  A  granite  may  be  turned  into  glass  by 
melting,  and,  if  it  has  little  quartz  and  no  mica,  into  clear 
glass ;  and  bottle-glass  has  been  made  out  of  some  kinds  of 
trap.  Conversely,  any  glass,  if  subjected  in  a  furnace  to  a 
bright  red  heat  (short  of  the  heat  of  fusion)  for  three  or 
four  weeks  will  pass  more  or  less  completely  to  the  litlioid 


442 


DESCRIPTIONS   OF   ROCKS. 


or  stony  state — that  is,  become  devitrified,  or  converted  into 
stone.  Part  of  the  molecular  difference  of  stone  and  glass 
is  manifested  in  the  inferior  specific  gravity  of  the  latter. 
Thus  in  the  case  of — 

As  Stone.   As  Glass.  As  Stone.  As  Glass. 

Quartz G.=  2'65     '219         Augite G.  =  3'27        2*80 

Orthoclase...         2'58        2'31  Chrysolite..         3'38        318 

Labradorite..         2'73        2'57  Doleryte...         2'95        2'84 

Hornblende..         3'21        2'82  Trachyte...         2'58        2'45 

The  names  pitclistone  and  pearlstone  are  applied  to  some 
of  the  intermediate  stages  between  stone  and  glass;  and 
the  name  obsidian,  to  volcanic  glass  of  trachytic  or  rhyolitic 
outflows  ;  tachylite,  to  that  of  basaltic.  Figures  4,  5  (from 
Zirkel),  and  6  (from  Eosenbusch)  represent,  much-magni- 
fied, transparent  slices  from  glassy  rocks  in  three  of  their 
stages;  Fig.  4  of  obsidian,  containing  radiating  clusters 
of  hair-like  microlites  (or  microscopic  minerals),  called 
trichites  (from  the  Greek  thrix,  hair),  such  as  are  common 
in  all  obsidians ;  Fig.  5,  of  pearly  te,  a  light-gray  rock  of 


4. 


5. 


6. 


"111 


Trichites  in  Ob- 
sidian. 


Trichites  and  Fluidal       Microlites  in  Pitch- 
texture  in  Pearlyte.     stone  from  Weissenberg. 


pearly  lustre  from  the  Nevada  Basin,  having  its  trichite 
clusters  very  numerous,  and  arranged  in  lines  or  planes, 
and  some  of  the  trichites  powdered  with  pellucid  grains, 
or  globulites,  which  are  incipient  crystals ;  Fig.  6,  of  pitch- 
stone,  from  Weissenberg,  in  which  the  microlites  are  dis- 
tinctly crystalline  in  form,  and  some  give  evidence  that 


DISTINCTIONS   AMONG   ROCKS. 


443 


they  are  feldspar  crystals,  others  that  they  are  augite  and 
magnetite,  arid  indicate  that  the  rock  is  intermediate  be- 
tween a  glass  and  a  basalt.  Thus  there  is  a  passage  toward 
ordinary  stone.  The  slags  of  furnaces  are  of  the  nature  of 
an  obsidian  or  a  tachylite,  or  of  some  of  the  stages  between 
it  and  stone ;  and  they  often  illustrate  igneous  rocks  in 
their  microlitic  and  mineral  structure.  Figure  7  repre- 
sents a  section  much  enlarged  of  a  slag  found  in  the  soil 
over  which  a  stack  of  wheat-straw  had  been  burned.  The 
crystals  No.  1  are  melilite;  2,  the  mineral  tridymite, 
(which  occurs  in  cavities  in  the  obsidians  of  the  Yellow- 
stone Park) ;  3,  indeterminate  acicular  microlites;  and  4, 
air-vesicles.  Figure  8  is  the  same  from  a  limekiln  slag  in 
France ;  and  its  minerals  and  aspect  are  those  of  a  section 
of  doleryte  or  basalt  (as  the  author  of  the  article,  M.  Ch. 
Velain,  observes):  1  being  magnetite,  2  augite,  and  3 
labradorite  in  lath-shaped  crystals.  The  cavities  (4)  in 
the  latter  are  described  as  often  coated  with  acicular  crys- 
tals. 


7. 


Slag  from  the  burning  of  a 
stack  of  wheat-straw. 


Slag  from  a  limekiln,  basalt- 
like  in  composition. 


Eruptive  rocks,  when  looking  as  if  stone  throughout, 
often  have  glassy  particles  among  the  stony.  If  they  have 
come  up  through  a  fissure,  the  part  near  the  walls  of  the 


444 


DESCKIPTIOXS   OF   ROCKS. 


fissure  may  contain  particles  of  glass,  and  the  interior  of 
the  mass  none.  Many  igneous  rocks  have  glassy  grains 
among  the  stony  grains,  or  a  glassy  base,  because  the  cool- 
ing was  not  slow  enough  for  complete  lapidification.  Such 
9.  portions  of  a  rock  are  described  as  unin- 

dividualized.  An  unindividuaiized  base 
exists  in  the  basalt  of  Truckee  Valley, 
the  character  of  -a  slice  from  which, 
highly  magnified,  is  given  in  Fig.  9  (from 
Zirkel) ;  here,  feldspar  crystals,  of  their 
usual  lath-like  forms  (part  of  them  sani- 
din),  a  largish  crystal  of  chrysolite,  and 
smaller  irregularly  shaped  augites,  are 
imbedded  in  a  glassy  base  in  which  are 
extremely  small  globulite  grains  that  are 
globules  of  devitrified  glass  or  incipient 
crystals.  The  glassy  unindividuaiized 
base  occupies  the  spaces  among  the  crys- 
Basalt  with  the  base  talline  portions. 

unindividuaiized.  The  presence  of  some  glass  in  the 
ground-mass  or  base,  when  this  is  the  only  difference,  is 
not  of  great  geological  importance.  It  is,  however,  the 
chief  characteristic  separating  rhyolyte  (quartz-trachyte) 
from  quartz -felsyte,  trachyte  from  quartzless  felsyte,  basalt 
from  diabase,  andesyte  from  dioryte,  etc. 

e.  Fliiidal  or  not. — Eruptive  rocks  in  thin  slices  under 
the  microscope  often  exhibit  wavy  lines  or  bands,  which 

11. 


Rhyolyte;  Fluidal  texture. 


Broken  Crystal. 


are  evidence  of  movement,  or  flowing,  when  in  the  liquid 
state.  One  variety  of  this  texture,  in  a  Nevada  rhyolyte, 
is  represented  in  Fig.  10  (from  Zirkel) ;  and  another  in 
Fig.  5,  on  page  442.  A  somewhat  similar  appearance  occurs 


DISTINCTIONS   AMONG   ROCKS.  445 

at  times  in  fine  sedimentary  beds,  due  to  flow  of  the  waters 
during  their  deposition.  Broken  crystals,  also,  are  often 
evidence  of  movement  of  some  kind  in  an  igneous  rock ;  it 
may  be  that  from  contraction  on  cooling,  as  well  as  that  of 
flow  before  solidification.  Fig.  11  shows  an  example  from 
a  microscopic  section  of  a  labradorite  rock  (the  bands  are 
those  developed  by  polarized  light  in  a  triclinic  feldspar). 

Fluidal  lines  and  texture  have  been  produced  also  in 
solid  crystalline  rocks  by  powerful  movement  of  one  mass 
of  rock  on  another  along  with,  at  times,  some  metamorphic 
change,  and  they  may  be  evidence  01  such  movement. 

f.  Splierophyric  or  not. — In  consolidation  from  fusion, 
especially  when  the  fused  material  is  in  the  state  of  glass, 
there  is  often  a  tendency  to  segregation  around  centres, 
and  thus  to  the  production  of  spJierulites  or  globular  con- 
cretions. Spherulites  have  generally  a  radiated  structure  ; 
but  other  concretions  consist  often  of  concentric  layers.  Ob- 
sidian and  pearlstone  are  very  of  ten  "  spherulitic,"  and  some- 
times full  of  large  as  well  as  small  concentric  concretions, 
either  kind  consisting  of  orthoclase  with  some  quartz ;  and 
concretions  of  different  constitution  occur  in  other  kinds 
of  igneous  rocks,  and  sometimes  also  in  metamorphic  rocks. 
The  character  distinguishes  only  varieties.  The  term  sphe- 
rophyric  (similar  to  those  describing  a  porphyritic  struc- 
ture, p.  441)  is  applied  beyond  to  the  variety  under  any 
crystalline  rock  which  has  a  spherulitic  or  concretionary 
structure.  The  structure  is  different  from  concretionary 
by  deposition  around  centres,,  such  as  is  exemplified  in  oo- 
litic and  pisolitic  limestone  and  in  clay-stones.  Amygdules 
differ  from  either  in  that  they  are  made  by  deposition  in 
small  vapor-made  cavities  similar  to  those  of  a  cellular 
lava. 

4.  Based  on  Supposed  Distinctions  in  Age. 

Small  differences  in  the  texture  of  igneous  rocks  have 
been  regarded  as  sufficient  for  an  offhand  distinction  of  a 
kind  of  rock  into  an  earlier  and  a  later  section,  and  for  the 
introduction  of  separate  names  for  the  two.  Such  names 
as  earlier  diabase  and  later  diabase,  earlier  dioryte  and 
later  dioryte,  earlier  felsyte  and  later  felsyte,  the  earlier 
including  (or  thought  to)' the  part  older  than  the  Tertiary 
era  of  geology,  have  been  used;  and  also  the  name  diabase 
has  been  restricted  to  the  earlier,  and  dolcryte  or  basalt  used 


440  DESCRIPTIONS   OF   ROCKS. 

for  the  later,  masses  of  a  single  kind  of  rock.  Since  all 
grades  of  texture,  from  granite- like  (granitoid)  to  scoriace- 
ous  and  glassy,  may  occur  in  the  same  mass  of  igneous  rock, 
whether  of  Tertiary  age  or  older,  the  distinction  has  not 
the  value  formerly  supposed. 

The  same  principle  holds  true  as  regards  most  metamor- 
phic  rocks.  The  common  minerals  of  these  rocks — the 
feldspars,  micas,  and  chlorites — belong  to  no  particular  age. 

The  only  common  minerals  of  metamorphic  rocks  that 
are  now  supposed  to  be  confined  to  the  Archaean — eruptive 
rocks  excluded — are  the  accessory  species,  chondrodite, 
phlogopite,  zircon,  nephelite,  the  scapolites;  and  other 
common  species  that  are  much  more  abundant  in  Archaean 
metamorphic  rocks  than  in  later  are  apatite,  augite,  horn- 
blende, chrysolite,  graphite,  titanite,  corundum,  menacca- 
nite,  hematite,  magnetite ;  while  those  less  abundant  in 
Archaean  than  in  later  metamorphic  rocks  are  micas,  chlo- 
rites, and  the  accessory  minerals,  garnet,  staurolite,  fibrolite, 
cyanite,  andalusite,  and  tourmaline. 

As  to  rocks :  hornblendic  and  augitic  gneisses  and  gran- 
ites, syenyte,  quartz-syenyte,  zircon-syenyte,  coarsely 
crystalline  dioryte,  and  other  granitoid  hornblendic  or 
augitic  rocks,  with  epidote  and  nephelite  rocks,  prevail  most 
among  the  metamorphic  rocks  of  Archaean  time. 

5.   The  Distinction  of  Eruptive  and  Metamorphic. 

Many  crystalline  rocks  occur  of  both  eruptive  and  meta- 
morphic origin.  Some  examples  of  this  among  the  massive 
rocks  are  granite,  syenyte,  felsyte,  dioryte,  gabbro,  doleryte 
or  diabase.  There  are  also  others  among  schistose  rocks  ; 
for  a  schistose  structure  is  now  known  to  be  a  possible  result 
of  pressure  during,  or  subsequent  to,  the  cooling  of  an 
eruptive  rock,  as  well  as  during  the  formation  of  a  meta- 
morphic rock.  Further:  in  the  alteration  of  an  augitic 
rock  to  a  hornblendic,  a  hornblende  schist  is  sometimes 
produced.  Massive  structure  is  hence  no  certain  evidence 
of  eruptive  origin;  and  neither  is  schistose  of  metamorphic, 
although  generally  indicating  it.  Hence  any  attempt  to 
divide  off  crystalline  rocks  into  eruptive  and  metamorphic 
is  necessarily  unsatisfactory.  Among  rocks,  only  the  fol- 
lowing are  believed  by  most  petrologists  to  be  invariably 
metamorphic :  quartzyte,  mica  schist,  hydromica  schist, 


INVESTIGATION   OF   ROCKS.  447 

chlorite  schist,  talcose  schist,  argillyte  or  phyllyte,  serpen- 
tine; and  until  recently  serpentine  and  even  quartzyte  had 
been  placed  among  eruptives. 

III.  INVESTIGATION  OF  ROCKS. 

The  constituents  of  a  rock  are  usually  in  a  granular  state, 
and  the  ordinary  methods  of  determining  their  mineral 
nature  are  often  insufficient.  When  so  coarse  that  they  can 
be  studied  with  an  ordinary  pocket-lens,  the  texture  and 
the  methods  of  study  are  said  to  be  macroscopic  (the  prefix 
macro  being  from  the  Greek  makros,  large);  and  when  too 
finely  granular  for  this  method  of  study,  the  term  micro- 
scopic is  used.  , 

The  macroscopic  study  of  rocks  is  essentially  that  of 
ordinary  mineralogy,  while  the  microscopic  requires  that 
transparent  sections  of  the  rock  should  be  made  for  micro- 
scopic examination  with  ordinary  and  polarized,  light,  and 
by  other  means. 

1.  Thin  Sections. — To  make  the  sections:  first  take  a 
thin  chip  from  the  rock,  \  to  f  inch  across,  and  grind  it  to 
a  smooth  surface  on  a  revolving  iron  plate,  fed  with  fine 
emery  (No.  70)  and  water.  Next  secure  the  chip  by  the 
flat  surface  to  a  piece  of  glass  by  means  of  a  little  Canada 
balsam,  and  grind  the  opposite  side  in  a  similar  way,  and 
continue  the  grinding  until  the  section  is  quite  thin;  after 
which  use  finer  emery  and  greater  care,  in  order  to  reach 
the  requisite  thinness  and  transparency  without  breaking 
or  wholly  wasting  the  specimen.  The  Canada  balsam  used 
is  first  heated  on  the  glass  until  the  volatile  part  is  driven 
off,  but  not  until  it  is  made  brittle  if  cooled;  and  air- 
bubbles  are  carefully  excluded  in  attaching  the  piece  of 
rock  to  it.  The  section  thus  made  is  then  mounted  by 
transferring  it  to  the  middle  of  a  glass  slide  (for  which  a 
convenient  size  is  50  mm.  long  and  28  mm.  wide),  made 
ready  with  balsam;  and,  with  this  end  in  view,  the  glass 
used  in  the  grinding  is  first  heated  to  soften  the  balsam, 
and  then  the  section  is  pushed  from  it  with  a  knife-blade 
on  to  the  prepared  slide.  Before  the  transfer,  a  thin  cover 
of  glass  is  put  over  the  section  with  a  little  balsam;  the 
transfer  is  thus  facilitated.  Air-bubbles  are  scrupulously 
guarded  against ;  and  if  found  in  the  prepared  slide,  the 
mounting  has  to  be  repeated. 


448  DESCRIPTIONS  OF  BOCKS. 

•2.  Distinctive  Non-optical  Characters  Investigated. — 
The  slicing  makes  thin  sections  of  all  the  crystals  and  grains 
present.  Consequently,  the  forms  of  such  sections  of 
crystals  are  studied.  Equilateral  forms  are  looked  for  in 
isometric  crystals;  square  and  rhombic  forms  in  octahedrons; 
square  and  6-sided  in  cubes;  6-sided  and  4-sided,  and  others, 
in  dodecahedrons  (of  garnet,  etc.);  6-  and  8-sided  in  trape- 
zohedrons;  square  and  rectangular  and  8-sided  in  tetragonal 
crystals;  rectangular,  rhombic,  and  6-sided  in  orthorhombic 
and  monoclinic;  and  rhombic  and  scalene  forms  in  the 
case  of  triclinic  species.  But  it  is  to  be  noted  that,  besides 
these,  other  forms  will  occur  under  each  of  the  systems  of 
crystallization,  arising  from  oblique  sections  in  different 
directions,  and  from  the  frequent  distorted  forms  of  crys- 
tals. Further,  when  the  section  is  one  at  right  angles  to 
the  vertical  axis  it  has  the  interfacial  angle  of  the  prism. 

Again,  cleavage  lines  are  often  distinct,  and  among  them 
some  will  be  pretty  sure  to  have  between  them  the  cleavage 
angle  of  the  species:  for  example,  the  124°  and  56°  of 
hornblende,  or  87°  5'  and  92°  55'  of  pyroxene,  etc.;  and 
they  may  indicate  the  direction  of  the 
vertical  axis  in  a  prismatic  crystalline 
form.  The  grains  may  indicate  the 
species  also  by  the  character  of  the  in- 
tersecting cracks,  and  other  features. 

The  microscopic  objects  inside  of 
crystals  are  of  special  interest.  These 
inclosures  may  be  habitual  in  a  mineral; 
they  may  be  arranged  symmetrically  or 
concentrically,  as  in  leucite  (Fig.  12), 
or  in  parallel  planes,  so  as  to  indicate 
the  crystalline  form,  if  not  the  species. 
The  inclosure  may  be  a  globule  of  air  alone,  and  remain 
fixed  as  the  slide  is  changed  in  position;  or  a  liquid  may 
partly  fill  it,  and  the  air-bubble  move  as  the  position  of 
the  slide  is  changed.  The  liquid  may  be  water,  or  a  kind 
of  mineral  oil,  or  carbonic  acid  (Fig.  13),  liquids  that  differ 
in  boiling-points,  and  so  admit  of  identification  if  the  mi- 
croscope has  attachments  for  the  purpose.  If  it  is  car- 
bonic "acid  (COJ,  the  air-bubble  will  disappear  at  a  tem- 
perature of  86°-95°  F.  Liquid  C02  requires  a  pressure  of 
atmospheres  at  32°  F.  to  keep  it  liquid,  and  it  there- 


INTESTIGATIOST   OF   KOCKS. 


449 


fore  occurs  encased  only  in  hard  and  firm  minerals,  like 
quartz  and  topaz.  The  liquid  may  contain  crystals,  as,  for 
example,  a  cube  of  salt  (Fig.  14)  (showing  that  it  is 
probably  salt  water),  or  other  kinds  of  crystals.  Some  of 
the  microlites  of  an  igneous  rock  are  figured  on  page  442. 
Other  investigations  are  made  on  the  section,  while  it  is 


14. 


Liquid  Carbonic 
acid;  c,  air-bubble. 


Cube  of  Salt  in  a  solu- 
tion of  the  same. 


Magnetite  in  grouped 
crystals. 


upon  the  stage  of  the  microscope,  by  means  of  acids  (see 
p.  92,  and  beyond),  to  test  the  presence  of  lime,  soda,  sul_- 
phur,  iron,  phosphorus,  titanium,  fluorine,  carbonic  acid 
in  carbonates,  as  to  the  gelatinizing  or  not  of  the  silica 
present.  A  series  of  reactions  made  with  hydrofluoric  acid 
has  been  worked  out  by  Boricky,  and  may  be  found 

17. 


Garnet  crystal  with  a 
border  of  chlorite. 


Chrysolite  altered  in  part 
to  serpentine. 


described  in  works  on  Petrography.  The  fusibility  may  in 
some  cases  be  tried,  and  other  effects  of  heat,  when  pro- 
vided with  proper  attachments  for  the  purpose. 


450  DESCRIPTIONS   OF  BOCKS. 

The  tendency  to  oxidation  or  other  alteration  in  some 
minerals  has  often  produced  a  clouded  or  discolored  margin 
in  certain  kinds  of  grains,  that  serve  as  a  distinguishing 
character ;  iron-bearing  minerals,  as  hornblende,  augite, 
garnet,  magnetite,  etc.,  often  having  a  rusty  margin  from 
iron-oxidation,  or  a  green  chlorite-like  margin  from  change 
to  a  chlorite  (Fig.  16);  and  chrysolite  grains  or  crystals 
have  often,  along  irregular  intersecting  fracture -lines, 
serpentinous  and  rusty  material  and  magnetite  (Fig.  17). 

Incipient  alteration  produces  also  at  times,  especially  in 
pyroxene  and  hypersthene,  a  peculiar  lustre  arising  from 
minute  points  of  materials  developed  within,  and  the  pro- 
cess has  been  named  (by  J.  W.  Judd),  from  the  name 
schiller  spar  (or  its  German  origin),  schillerization ;  and, 
accompanying  this,  there  is  a  tendency  in  pyroxene  to  be- 
come laminated,  or  to  pass  to  a  diallage. 

3.  Optical   Characters   Investigated. — The   methods  of 
optical  investigation  are  briefly  described  on  pages  70-80. 
With  thin  sections,  observations  are  made  to  ascertain  the 
existence  of  pleochroism  or  not  in  colored  minerals,  and  its 
characters  when  existing ;    whether,  with  crossed   nicols, 
there  is  a  change  from  dark  to  light,  or  not,  as  the  section 
on  the  stage  is  revolved;  for  if  not,  the  substance  is  amor- 
phous, like  glass,  or  isometric,  or,  it  may  be,  an  air- vesicle; 
whether  the  optical  characteristics  are  those  of  uniaxial  or 
biaxial   crystallization,   or   of  circular  polarization   as   in 
quartz;  what  the  position  of  the  plane  of  the  optic  axes; 
whether  extinction  is  parallel  or  inclined;  and  what  the 
angle  of  extinction  if  inclined;  whether  there  is  a  twinned 
or  compound  structure,  a  simple  twinning  or  polysynthetic; 
and  so  on.     The  twinning  and  cleavage  lines  often  aid  in 
determining  the  direction  of  the  vertical  axis,  and  thus  in 
orientating  the  object  (giving  it  its  normal  position). 

4.  Other  points  investigated. — Besides  the  study  of  min- 
eral distinctions,  there  is  the  microscopic  study  of  mineral 
changes  and  the  kinds  and  origin  of  transformation  in 
rocks. 

The  changes  studied  include  also  (1)  methods  of  consolida- 
tion; (2)  crystallization;  (3)  paramorphic  transformations; 
(4)  chemical  transformations;  (5)  mechanical  movements. 

a.  In  consolidation. — The  consolidation  sometimes  de- 
velops crystalline  forms.  In  the  case  of  a  siliceous  sand- 
stone there  are  ordinarily  additions  to  the  exterior  of  the 


INVESTIGATION   OF   ROCKS. 


451 


original  grains,  turning  them  into  crystals  of  quartz.    Grains 

of  a  quartz  sandstone  are  always  parts  of  quartz  crystals 
having  crystallographic  axes;  and 
the  material  added  in  the  consoli- 
dation is  added  in  subordination  to 
these  axes,  as  shown  first  by  Torne- 
bohm  and  Sorby.  It  is  illustrated 
in  Fig.  18,  an  enlarged  view  of  one 
of  the  grains  of  the  Potsdam  sand- 
stone of  New  Lisbon,  Wisconsin 
(A.  A.  Young).  In  this  way  sand- 
beds  have  become  an  aggregation 
of  minute  crystals,  although  gener- 
ally failing  of  this  because  of  the 
filling  of  the  interstices.  The 
same  happens  with  grains  of  feld- 
spar and  hornblende  (Irving,  Van  Hise). 

b.  In  paramorphic  changes. — The  paramorphic  change 

of  pyroxene  to  hornblende  is  well 

traced  out   under  the  microscope. 

The  figure  (from  Hawes)  represents 

a  crystal  of  augite  changed  to  horn- 
blende except  over  a  central  portion, 

as  the  cleavage  angles  in  the  two 

parts  show.      The  change   is  not 

always  a  paramorphic  change  alone, 

for  there   is  often  some  loss  and 

gain  of  ingredients   attending  the 

change,  the  -pyroxene  often  losing 

in  lime  and  gaining  in  magnesia. 

This  kind  of  change  has  great  geo- 


19. 


Pyroxene  changed  to 
Hornblende  (Uralite). 


logical  importance,  since  it  is  now  known  that  many  horn- 
blende rocks,  supposed  to  be  eruptive,  have  been  thus  made; 
and  that  many  hornblendic  Archaean  rocks  have  had  the 
same  kind  of  origin.  Hypersthene  undergoes  a  similar 
transformation. 

The  change  of  pyroxene  to  hornblende,  first  noticed  by  Rose  in 
1831,  was  regarded,  until  recent  years,  as  only  a  local  occurrence. 
But  ten  years  since,  in  November  of  1876,  Mr.  S.  Allpcrt  described 
the  "  dolcrytes"  of  Land's  End  as  more  or  less -altered  to  hornblende 
rocks,  reporting  that  some  portions  had  become  "  half-formed  horn- 
blende-schist;" and  his  paper  gives  examples  of  the  same  from  half  a 
dozen  other  English  localities.  The  change  was  recognized  also  by 


452 


DESCRIPTIONS   OF  ROCKS. 


Streng  and  Wichmann  in  1876,  and  afterward  by  Pumpelly,  Irving, 
and  Wadsworth,  among  the  "greenstones"  and  other  eruptive  rocks 
of  Michigan  and  Wisconsin.  In  1878,  G.  W.  Hawes  pointed  out,  in 
his  report  on  the  rocks  of  N.  Hampshire  (Geol.  N.  H.,  iii  205),  the 
derivation,  through  the  same  kind  of  change,  of  a  hornblende-syenyte 
from  "  augite-syenyte"  of  three  N".  Hampshire  localities,  one  on 
Little  Ascutney  Mountain.  In  1883,  Irving  and  Van  Hise  announced 
that  the  hornblende  gneisses,  granites,  and  syenytes  of  the  Wisconsin 
Archaean  had  been  derived  from  augitic  gneisses,  granites,  and  syenytes; 
and  G.  H.  Williams  further  illustrated  this  subject  in  1884.  In  1886 
Van  Hise  showed  that  mica  had  been  made  from  feldspar. 

The  change  in  the  aragonite  of  a  limestone  to  calcite 
takes  place  at  the  time  of  crystallization,  and  this  may  be 
either  before  or  during  the  time  of  metamorphism;  and 
that  to  dolomite  takes  place  probably  at  the  time  of  original 
consolidation  of  the  calcareous  sands,  the  half-evaporated 
waters  of  a  sea-border  marsh  affording  the  magnesia. 

Another  example  of  a  paramorphic  change  is  that  of  the 
mineral  andalusite  (G.  =•  3'1)  to  cyanite  (G.  =3*56).  The 
tendency  to  the  change  is  strong,  andalusite  crystals  often 
being  altered  within.  In  its  incipient  stage  the  interior 
has  often  the  structure  represented  much  magnified  in  Fig. 


20. 


21. 


20,  and  in  the  later,  that  in  Fig.  21  (both  from  Hawes),  in 
which  the  andalusite  prism  is  made  up  of  small  prismatic 
forms  of  cyanite. 

c.  In  chemical  changes.- — Some  of  the  chemical  changes 
that  are  microscopically  studied  are  those  of  chrysolite  and 
other  minerals  to  serpentine  (p.  330);  of  augite  to  hyper- 
sthene  or  enstatite;  of  augite  (with  some  aid  from  feldspar) 
to  chlorite  or  to  epidote;  of  hornblende  similarly  to  chlorite 
or  epidote  or  biotite;  of  garnet  to  chlorite;  of  orthoclase  to 
mica;  of  menaccanite  to  leucoxene;  of  magnetite  to  limon- 
ite;  and  of  the  beclouding  of  the  feldspars  and  their  change 
to  saussurite,  or  to  chlorite,  etc. 


INVESTIGATION   OF   BOCKS. 


453 


In  these  chemical  changes  some  ingredients  are  usually 
set  free;  and  these  are  often  left  in  part  within  the  space  of 
the  original  mineral,  arranged  concentrically  along  its  lines 
of  cleavage,  or  in  its  rifts,  or  scattered  about  outside.  The 
iron  discharged  takes  the  form  of  magnetite,  or  hematite, 
menaccanite,  picotite,  or  chromite,  or  sometimes  native 
iron. 

Fig.  22  (from  Hawes)  shows  the  magnetite  as  it  occurs 


Altered  Hornblende. 


Partially  altered  Chrysolite  . 


often  in  altered  hornblende,  and  also  biotite  (centre  of  fig- 
ure) and  calcite  (lath-shaped  grains),  which  are  likewise 
products  of  the  alteration.  The  magnetite  is  a  common 

Eroduct  in  the  change  of  chrysolite  to  serpentine  (Fig.  23, 
-om  Judd),  representing  (enlarged 
100  diameters)  partially  altered 
chrysolite  with  the  products  of  de- 
composition along  the  rifts.  Lime 
is  often  discharged  in  augitic  and 
hornblendic  alterations,  and  if  CO, 
is  present,  calcite  is  formed,  as  in 
Fig.  22.  Silica  is  also  often  set 
free;  and  liquid  globules  of  the  C02, 
if  present,  often  become  enclosed 
in  the  crystallizing  quartz.  Men- 
accanite (titanic  iron)  changes  to  a 
grayish  white  or  whitish  material 
called  leucoxene  (see  p.  312),  which 
has  often  a  reticulated  appearance  (Fig.  24,  from  Hawes) 
owing  to  the  progress  of  the  change  along  cleavage  lines  or 
rifts. 


Leucoxene  from  Menac- 
canite. 


454  DESCRIPTIONS  or  ROCKS. 

Such  changes  are  very  different  from  the  oxidations  due 
to  surface  weathering,  which  are  another  subject  of  study. 

For  a  large  part  of  the  chemical  changes  carried  on  iJiroughout  the 
mass  of  the  rock,  (1)  the  presence  of  moisture  was  required,  many  of  the 
minerals  formed,  as  serpentine,  chlorite,  zeolites,  etc.,  being  hydrous; 
(2)  also  the  presence  of  carbonic  acid,  calcite  being  a  very  common 
product;  (3)  also,  for  some  of  the  changes,  other  vaporizable  ingredients, 
including  metallic  compounds  or  vapors.  The  introduction  of  the 
vapors  into  the  rock  and  their  general  diffusion  could  have  taken 
place  only  when  the  rock  was  melted,  and  therefore  only  while  it  was 
rising  from  the  depths  below.  The  liquid  rock,  at  a  temperature  be- 
tween 1500  and  2500  F.,  should  it  pass,  in  the  ascent,  rocks  containing 
some  moisture  (0'6  p.  c.  would  be  a  pint  to  a  cubic  foot,  capable  of 
yielding  nearly  30  cubic  feet  of  vapor  at  the  ordinary  pressure),  or  en- 
counter subterranean  streams  (whose  waters  might  be  saline  or  mineral), 
vapors  in  great  volume  would  be  sure  to  form  and  be  forced  to  enter  the 
upward-moving  rock  (without  upward  movement  in  the  liquid  rock  they 
could  not  enter  or  take  the  form  of  vapor);  or,  if  passing  a  limestone 
stratum,  CO2  would  escape  and  be  carried  up;  and  so  for  other  vaporiz- 
able materials.  The  hot  vapors  would  be  active  agents  among  the 
constituent  minerals,  and,  as  the  right  temperature  was  reached,  would 
begin  destructive  and  reconstructive  work,  and  carry  it  on  with  such 
new  results  as  the  declining  temperature  favored .  And  thus  has  prob- 
ably come  many  of  the  changes  that  have  gone  on  throughout  the 
interior  of  rocks,  producing  from  the  original  minerals  the  chlorite,  so 
common,  the  serpentine,  saussurite,  the  quartz  in  crystallized  and 
chalcedonic  forms,  zeolites,  and  also  copper  ores,  silver  ores,  etc. 
The  aluminium-sodium  carbonate,  called  dawsonite,  was  one  of  the 
products  in  a  dike  of  felsyte  intersecting  limestone  near  Montreal. 

In  the  changes  where  vapors  are  concerned,  the  first 
effect  is  usually  an  incipient  beclouding  of  the  feldspars 
and  of  the  other  silicates;  but  when  carried  forward  by  heat 
without  or  with  but  a  feeble  supply  of  moisture,  as  appears 
to  have  been  the  fact  in  many  examples  of  the  paramorphic 
kind,  the  feldspars  may  remain  unaltered. 

Some  volcanic  glass,  when  highly  heated,  loses  much  vol- 
atile matter  (moisture  ?),  and  is  converted  into  pumice ;  a 
dacite-glass  lost  8 -9  per  cent.  (J.  W.  Judd.) 


IV.    MICROSCOPIC  CHARACTERS  OF  COMMON  ROCK 
CONSTITUENTS. 

1.  Isometric  or  Amorphous. 

Glass. — Optical  characters  of  an  amorphous  substance  (p.  70). 

Opal.— Outlines  not  angular;  no  cleavage-lines.  Often  concentric 
in  structure.  Sometimes  interference  colors,  due  to  internal  strains. 
In  diatoms  and  sponge-spicules,  no  colors. 


MICROSCOPIC  CHARACTERS. 


455 


Leucite. — Outlines  8-sided.  Uncolored.  Often  containing  concen- 
tric or  radiating  series  of  microlites  (Fig.  1,  page  448)  or  glass.  Often 
feeble  double  refraction  with  polysynthetic  twinning  bands,  crossing 
at  90°  or  45°. 

Garnet.— Outlines  6-,  8-,  and  4-sided,  or  irregular.  Pale  red  disk 
to  brown  and  nearly  colorless ;  irregularly  fractured.  Sometimes 
changed  at  the  margin  or  throughout  to  chlorite  (Fig.  16,  p.  449);  often 
contains  grains  of  quartz  or  other  inclusions. 

Magnetite.— Squares,  rhombs,  or  hexagonal  outlines,  often  in  den- 
dritic groups.  Opaque. 

Pyrite. — Outlines,  squares,  and  other  isometric  figures.  Opaque. 
Brass-yellow  by  reflected  light. 

2.  Tetragonal  and  Hexagonal. 

Quartz. — Outlines  sometimes  sections  of  quartz  crystals,  but  usually 
irregular.  No  cleavage  lines.  Field  never  wholly  dark  on  the  rotation 
of  a  nicol.  In  oblique  or  vertical  sections  interference  colors  brilliant; 
in  basal  sections,  if  they  are  not  too  thin,  the  characters  of  circular 
polarization.  By  reflected  light  the  quartz  grains  in  a  section  of  whitish 
granite  appear  darker  than  the  feldspar  grains.  Often  contain  glo- 
bules of  CO2. 

Tridymite. — Hexagonal  tables  (p.  262  and  443).  Interference  colors 
not  brilliant.  Polarization  not  circular,  but  crystals  usually  too  thin 
to  use  this  distinction. 

Nephelite.— Often  hexagons  and  rectangles.  Colorless.  Gelatin- 
izes; reactions  for  soda  (p.  92).  Inclosures  common,  and  often  hex- 
agonally  arranged. 

Tourmaline. — 3-,  6-,  and  9-sided  outlines.  No  vertical  cleavage 
lines;  never  finely  fibrous.  Strongly  dichroic. 

Scapolite. — Squares,  rectangles,  8-sided  sections.  Few  vertical 
cleavage  lines,  some  transverse.  Interference  colors  brilliant;  no 
dichroism. 

Zircon. — Squares,  etc.;  always  in  crystals;  no  cleavage  lines.  Not 
distinctly  dichroic.  Interf.  colors  brilliant. 

Apatite.-- -Hexagons,  long  rectangles,  needles;  cleavage  not  much 
distinct.  Often  having  dust-like  enclosures.  Reactions  for  lime  and 
phosphorus. 

Hematite. — Hexagonal  and  irregular  outlines.  Blood-red  to  orange 
in  very  thin  slices. 

Menaccanite  (Ilmcnite).— Similar  to 
hematite,  but  black  and  opaque  instead  of 
blood-red  in  thin  slices.  Often  a  grayish 
white  border  and  intersecting  lines  owing 
to  the  production  of  leucoxene  by  altera- 
tion (p.  453).  Reaction  for  titanium. 

Calcite,  Dolomite. — Grains  generally 
poly  synthetically  twinned  (Fig.  25),  the 
bands  parallel  to  the  longer  diagonal.  In- 
terference colors  feeble. 

Spherulites  also  give  in  polarized  light 
the  black  cross  of  a  uniaxial  substance, 
owing  to  the  radiated  structure;  the  cross 
revolves  with  the  revolution  of  the  plate.  Crystalline  Calcite. 


456  DESCRIPTIONS  OF  BOOKS. 

3.  Orthorhombic. 

Enstatite.— Prismatic,  often  fibrous.  Extinction  parallel  to  vert, 
axis,  or  cleavage-lines.  Interference  colors  very  brilliant.  Not  di- 
chroic. 

Hypersthene  (Amblystegite  included). — Like  cnstatite,  but  dichroie, 
yet  feebly  so  unless  containing  much  iron.  Usually  cleavage  parallel 
to  the  brachypinacoid.  Inclusions  parallel  to  this  plane  often  give  a 
metalloidal  lustre.  More  decomposable  than  pyroxene,  being  often 
altered  when  the  pyroxene  (as  seen  in  a  thin  slice)  is  fresh. 

Chrysolite  (divine). — Not  prismatic  in  habit,  nor  fibrous.  No 
regular  cleavage  lines,  but  irregular  rifts,  along  which  usually  altered 
to  greenish,  grayish,  and  brownish,  or  rusty;  or  changed  wholly  to 
serpentine  (p.  ),  and  then  often  containing  grains  of  magnetite, 
chromite,  or  picotite.  Not  dichroic.  Interf.  colors  brilliant. 

Staurolite. — Rhombic  or  6-sided  outlines,  and  crossed  forms  through 
twinning;  in  transverse  section  rhombic  angle  128°.  Cleavage  lines 
not  very  distinct.  Interf.  colors  brilliant.  In  small  clear  crystals 
strongly  dichroic.  Very  numerous  enclosures,  especially  grains  of 
quartz. 

Fibrolite  (Sillimanite).— Long  prismatic  to  fibrous;  longitudinal 
cleavage-lines.  Extinction  parallel  to  prismatic  lines.  Interf.  colors 
brilliant.  Not  dichroic.  No  tendency  to  alteration  like  that  of  andal- 
usite. 

Andalusite. — Prismatic,  not  fibrous;  basal  sections  nearly  square. 
Crystals  usually  altered,  imperfectly  polarizing,  containing  minute 
slender  secondary  crystals,  and  sometimes,  through  alteration,  having 
the  characters  of  cyanite.  Chiastolite  variety  has  a  regular  arrange- 
ment of  impurities,  which  are  partly  carbonaceous,  this  being  indi- 
cated by  the  loss  B.B.  of  the  color. 

Zoisite. — Six-sided  and  other  sections;  not  finely  fibrous.  Cleavage- 
lines  in  only  one  direction,  parallel  to  vertical  axis.  Interf.  colors 
usually  little  brilliant.  Not  dichroic. 

4.  Monodinic. 

Orthoclase. — Never  columnar  or  fibrous;  cleavage-lines  parallel  to 
clinodiagonal.  Twinning  never  poly  synthetic.  Optic-axial  plane  in 
the  clinode  section.  Extinction  angle  measured  with  axis  c  (or  verti- 
cal), 21°  7'.  Interf.  colors  rather  brilliant,  but  less  so  than  in  quartz, 
and  if  section  is  very  thin,  of  blue-gray  color  and  faint. 

Hornblende.— Sections  acute  rhombs  and  hexagons.  Prismatic, 
often  fibrous  and  granular;  in  transverse  sections  cleavage  lines  usually 
distinct  in  two  directions,  the  angle  124°  30',  but  in  vertical  sections 
only  vertical  lines.  Optic-axial  plane  in  the  clinode  section.  Extinc- 
tion angle  (with  axis  c)  usually  15°,  varying  between  2°  and  18°. 
Strongly  pleochroic;  usually  alternating  green  and  yellow  through  a 
basal  section  on  rotation  of  the  lower  nicol,  and  bluish  through  a  pris- 
matic section;  interference  colors  not  very  bright  with  the  black  horn- 
blendes. 

Pyroxene.— Prismatic  and  granular  ;  in  transverse  sections,  4- 
and  8-sided  outlines,  with  cleavage  lines  in  two  directions,  the  angle 
87°  5'.  Optic  axial  plane  in  clinode  section;  extinction  angle  (with 


DESCRIPTIONS  OF  ROCKS.  457 

axis  c)  usually  39°  (varying  to  54°),  the  angle  on  the  opposite  side  of  c 
from  that  in  hornblende.  Feebly  or  not  dichroic. 

Muscovite.— Hexagons  and  triangles  in  basal  sections,  but  oblique 
sections  lined  in  one  direction  from  edges  of  cleavage-lamina?.  Ex- 
tinction parallel,  as  in  orthorhombic  species.  Rather  feebly  dichroic. 
Optic-axial  angle  very  large,  and  the  plane  of  the  axes  macrode.  For 
biotite,  the  same,  but  optic-angle  very  small  to  0°  (p.  291),  and  strongly 
dichroic. 

Meroxene.— Similar  to  biotite,  but  optic-axial  plane  brachode. 

Epidote. — Sometimes  columnar,  not  very  fine  fibrous.  Cleavage 
lines  in  one  direction,  the  orthode.  Optic- axial  plane  clinode.  Ex- 
tinction angle  (on  c)  2°  29'.  Intcrf.  colors  brilliant.  Strongly  pleo- 
chroic. 

5.  Tridinic. 

Albite  and  other  Triclinic  Feldspars. — Cleavage  as  in  ortho- 
clase;  the  crystals  of  fine-grained  rocks  commonly  tabular,  parallel  to 
vertical  section  through  axis  a  (clinode  section  in  orthoclase),  and 
hence  showing  lath-like  forms  (Fig.  9,  p.  444)  in  thin  slices,  and 
usually  having  the  longer  side  in  the  direction  of  the  vertical  axis  (c). 
Generally  polysynthetic  twinning  in  such  sections  lengthwise  (not  ap- 
parent in  sections  transverse),  and  showing  usually  two  or  more  bands 
of  color  unless  too  thin  for  more  than  one.  Extinction  angle,  meas- 
ured on  the  edge  0/i4,  varying  for  the  species:  Albite,  3°  54'-4°  51'; 
microcline,  15°;  oligoclase,  2c-4° ;  labradorite,  5°-7°;  anorthite,  27°-37°. 

Cyanite  (Kyanite). — Prismatic  vertically  and  flattened  parallel  to 
i-l  (or  to  section  through  c);  cleavage-lines  in  the  prismatic  direction. 
Extinction  angle,  in  sections  parallel  to  i-l,  on  cleavage-lines  or  cor- 
responding edge,  30°,  but  very  thin  sections  required  for  the  trial. 


VI.  DESCRIPTIONS  OF  ROCKS. 

The  grander  subdivisions  of  rocks  here  adopted  are  three 
in  number : 

1.  CALCAREOUS  ROCKS  OR  LIMESTONES. 

2.  FRAGMENTAL  ROCKS,  NOT  CALCAREOUS. 

3.  CRYSTALLINE  ROCKS,  EXCLUSIVE  OF  THE  CALCARE- 
OUS. 

In  the  names  of  rocks,  the  termination  He  is  here  changed  to  yte,  as 
done  in  the  author's  "  System  of  Mineralogy"  (1868),  in  order  to  dis- 
tinguish them  from  the  names  of  minerals.  Granite  is  excepted. 

I.  Calcareous  Rocks  or  Limestones. 
1.  UNCRYSTALLINE. 

1.  Massive  Limestone. — Compact.  Colors  dull  gray,  blu- 
ish gray,  brownish,  and  black,  sometimes  yellowish  white, 
cream-colored,  nearly  white,  red  of  different  shades.  Tex- 


458  DESCRIPTIONS  OF  KOCKS. 

ture  varying  from  earthy  to  compact  semi-crystalline. 
Hardness  about  3,  and  hence  easily  scratched  with  the 
point  of  a  knife.  G.  =  2  -25-2  '75. 

In  constitution  ordinary  massive  limestone  varies  be- 
tween a  calcium  carbonate  or  non-magnesian  limestone, 
and  a  calcium  magnesium  carbonate  or  magnesian  lime- 
stone. The  two  kinds  are  undistinguishable  by  the  eye 
alone  ;  and  they  are  alike  also  in  losing  the  carbonic  acid 
when  heated  B.B.  (or  in  a  limekiln),  and  by  the  action  of 
acids,  as  already  explained.  The  non-magnesian  may  con- 
sist of  calcite,  or  of  calcite  with  much  aragonite,  since 
shells  and  other  organic  calcareous  secretions  are  often 
largely  aragonite.  Magnesian  limestone — since  it  has 
originated  from  calcareous  sediment  by  a  chemical  change 
through  magnesian  waters  (probably  sea-marsh  brines) — is 
less  likely  to  contain  aragonite  ;  it  may  be  true  dolomite  in 
composition  (p.  238),  but  it  is  generally  a  mixture  of  dolo- 
mite and  calcite. 

VARIETIES. — The  varieties  are  alike  under  the  above  kinds.  They 
differ  in  texture,  color,  presence  of  fossils  or  impurities,  and  in  other 
qualities.  Among  them  are  the  following:  a.  Compact,  b. 
Lamellar,  c.  Earthy,  of  which  chalk  is  a  white  calcite  variety,  d. 
Oolitic,  consisting  of  minutelj  concretionary  grains,  e.  Pisolitic,  con- 
sisting of  concretions  as  large  as  peas,  f .  Bird's-eye,  having  scattered 
crystalline  points,  as  in  a  limestone  of  western  New  York.  g.  Con- 
glomerate, a  calcareous  pudding  stone,  h.  Fossiliferous,  consisting 
chiefly  of  fossils,  i.  Coral  or  Madreporic,  containing  or  consisting  of 
fossil  corals,  j.  Encrinal  or  Crinoidal,  containing  disks  of  crinoids. 
k.  Nummulitic,  consisting  of  disk-shaped  fossils  called  nummulites. 
1.  Cherty,  containing  siliceous  nodules  or  layers. 

The  above  kinds  may  be  of  various  colors.  The  gray  and  black 
colors  are  commonly  due  to  carbonaceous  material;  for  they  burn 
white;  but  the  yellow  and  red  usually  to  the  presence  of  the  yellow  or 
red  iron-oxide. 

A  black  marble,  much  used  in  Eastern  U.  S.,  comes  from  Shoreham, 
Vermont,  and  other  places  near  L.  Champlain,  and  near  Plattsburg 
and  Glenn's  Falls,  N.  Y. ;  also  from  Isle  La  Motte.  A  pudding-stone 
marble,  of  various  dull  shades  of  color,  from  the  banks  of  the  Poto- 
mac, in  Maryland,  50  or  60  miles  above  Washington,  is  the  material 
of  columns  in  the  interior  of  the  Capitol  at  Washington. 

The  Portor  is  a  Genoese  marble  highly  esteemed  •"  it  is  deep  black, 
with  veinings  of  yellow;  the  most  beautiful  is  from  Porto- Venese. 
The  Nero-antico  is  an  ancient  deep  black  marble ;  the  Paragone,  a 
modern  one,  of  fine  black  color,  from  Bergamo;  and  Panno  di  morte, 
another  black  marble  with  a  few  white  fossil  shells. 

A  beautiful  marble  from  Sienna,  Brocatello  di  Siena,  has  a  yellow 
color,  with  large  irregular  spots  and  veins  of  bluish  red  or  purplish. 


DESCRIPTIONS   OF   HOCKS.  459 

The  Mandelato  is  light  red,  with  yellowish  Avhite  spots.  The  Madrc- 
poric  marble  is  the  Pietra  stellaria  of  the  Italians. 

Some  of  the  pyramids  of  Egypt,  including  the  largest,  the  pyramid 
of  Cheops,  is  made  of  nummulitic  limestone  ;  and  this  is  the  building 
material  of  Aleppo,  the  range  of  mountains  between  Aleppo  and  An- 
tioch  being  composed  largely  of  this  cream-colored  rock. 

A  soft  Tertiary  limestone  occurring  in  the  vicinity  of  Paris  has 
afforded  a  vast  amount  of  rock,  of  an  agreeable  pale  yellowish  color, 
for  fine  buildings  in  Paris  ;  arid  a  similar  rock  has  long  been  used  in 
Marseilles,  Montpellier,  Bordeaux,  Brussels,  and  other  places  in 
Western  Europe.  The  shell-rock,  or  Coquina,  of  St.  Augustine,  in 
Florida,  is  an  aggregate  of  shell  fragments  or  shell  sand. 

Fire-marble,  or  Lamachelle,  is  a  dark  brown  shell  marble,  having 
within  brilliant  fire-like  or  chatoyant  reflections. 

Ruin  marble  is  a  yellowish  marble,  with  brownish  shadings  or  lines 
arranged  so  as  to  represent  castles,  towers,  or  cities  in  ruins.  These 
markings  proceed  from  infiltrated  iron.  It  is  an  indurated  calcareous 
marl,  and  does  not  occur  in  large  slabs. 

Lithographic  stone  is  a  compact  limestone,  very  fine  and  even  in  tex- 
ture, and  of  light  gray  and  yellowish  color,  affording  a  very  even 
surface  good  for  use  in  lithography. 

Hydraulic  limestone  (Cement  stone,  in  part)  is  a  gray  impure 
limestone,  the  quicklime  from  which  makes  a  mortar  that  will 
set  under  water.  It  is  often  a  magnesian  limestone.  The  impur- 
ity is  the  source  of  its  hydraulic  character,  and  amounts  in  the 
best  to  20  to  80  per  cent,  by  weight  of  the  rock ;  it  is  clayey  or 
feldspathic  material,  consisting  chiefly  of  silica  and  alumina  in 
combination  with  free  silica.  The  hydraulic  limestone  (mag- 
nesian) of  Rondout,  N.  Y.,  afforded  on  analysis — besides  lime, 
magnesia,  and  carbon  dioxide— silica  15 '37,  alumina  913,  iron 
sesquioxide  2'25.  In  making  ordinary  mortal',  sand  (quartz)  is 
mixed  with  the  quicklime  and  water,  and  a  hydrate  of  calcium  is 
formed,  with  much  evolution  of  heat;  the  hardening  requires,  fur- 
ther, the  drying  away  of  the  water;  and  then  CO2,  of  the  atmosphere, 
becomes  combined  after  a  while  with  the  lime.  With  "hydraulic 
cement"  the  elements  of  the  clayey  impurity,  distributed  in  a  fine  state 
through  the  lime,  enter  into  combination  with  it,  and  hardening  goes 
on  while  water  is  present;  and  thus  it  "sets"  under  water.  An  arti- 
ficial hydraulic  cement  is  made  in  England,  by  mixing  70  p.  c.  of 
chalk  with  30  p.  c.  of  the  all'ivial  clay  or  mud  within  the  lower  tidal 
basins  of  the  Thames  and  the  Medway— the  mud  supplying  the  silica 
and  alumina  in  the  proper  condition;  and  this  makes  the  so-called 
Portland  cement. 

Carbonaceous  Oil-bearing  Limestones. — A  kind  used  for  building  in 
Chicago,  of  the  Niagara  period,  becomes  spotted  or  streaked  with 
blackish  mineral  oil,  after  a  few  years'  exposure  to  the  weather. 
Much  mineral  oil  and  gas  are  obtained  by  boring  into  the  Trenton 
limestone  in  northwestern  Ohio. 

Much  of  the  common  limestone  of  the  United  States  is  magnesian. 
That  of  St.  Croix,  Wisconsin,  the  "  Lower  Magnesian,"  afforded 
Owen  42 '43  per  cent,  of  magnesium  carbonate. 

In  some  limestones  the  fossils  are  magnesian,  while  the  rock  is  com- 


460  DESCRIPTIONS  OF  EOCKS. 

mon  limestone.  Thus,  an  Orthoceras,  in  the  Trenton  limestone  of 
Bytown,  Canada  (which  is  not  magnesian),  afforded  T.  S.  Hunt,  Cal- 
cium carbonate  56'00,  magnesium  carbonate  37*80,  iron  carbonate  5 '95 
=  99-75.  The  pale  yellow  veins  in  the  Italian  black  marble,  called 
"Egyptian  marble"  and  "portor"  (see  above),  are  dolomite,  accord- 
ing to  Hunt;  and  a  limestone  at  Dudswell,  Canada,  is  similar. 

2.  Marl. — A  clayey  or  earthy  deposit  containing  a  large 
proportion  of  calcium  carbonate — sometimes  40  to  50  per 
cent.     If  the  marl  consists  largely  of  shells  or  fragments 
of  shells,  it  is  called  Shell-marl. 

3.  Travertine. — A  massive   limestone   (calcium  carbon- 
ate), formed   by  deposition  from  calcareous    springs    or 
streams  (see  p.  236).    It  is  usually  cellular,  and  more  or  less 
concretionary.     A  handsome  compact  banded  kind,  trans- 
lucent, and  of  great  beauty,  comes  from  Tecali,  about  35  m. 
from  the  city  of  Mexico. 

Stalagmite  has  a  similar  origin. 

2.  CRYSTALLINE  LIMESTONE. 

Granular  or  Crystalline  Limestone.  (Marble.) — Lime- 
stone having  a  crystalline-granular  texture,  white  to  gray 
color,  but  sometimes  of  reddish  and  other  tints  from  im- 
purities. It  is  in  most  cases,  if  not  all,  a  metamorphic  rock, 
and  was  originally  common  limestone. 

Like  common  limestone,  it  may  be  either — 

I.  Calcyte,  calcium  carbonate,  more  or  less  pure. 

II.  Dolomyte,  calcium-magnesium  carbonate. 

III.  Galcitic  Dolomyte,  a  mixture  of  calcite  and  dolomite, 
much  more  common  as  a  rock  than  pure  dolomite.      It 
contains  no  aragonite,  the  crystallization  undergone  chang- 
ing this  mineral  to  calcite. 

The  impurities  are  often  mica,  tremolite,  white  or  gray 
pyroxene,  scapolite,  pyrite  ;  sometimes  serpentine,  through 
combination  with  which  it  passes  into  ophiolyte;  occasion- 
ally talc,  chondrodite,  phlogopite,  apatite,  corundum,  chlor- 
ite, spinel,  graphite,  etc.  Talc,  tremolite,  pyroxene,  chlor- 
ite, and  serpentine  are  common,  especially  in  the  dolomitic 
kinds. 

VARIETIES.— a.  Sfrttuary  marble;  pure  white  and  fine  grained,  b. 
Decorative  and  Architectural  marble ;  coarse  or  fine,  white,  and  mot- 
tled of  various  colors,  and,  when  good,  free  not  only  from  iron  in  the 
form  of  pyrite,  but  also  from  iron  or  manganese  in  the  state  of  car- 


DESCRIPTIONS   OF   ROCKS.  461 

bonate  with  the  calcium,  and  also  from  all  accessory  minerals,  even 
those  not  liable  to  alteration,  and  especially  those  of  greater  hardness 
than  the  marble  which  would  interfere  with  the  polishing.  Calcitic 
dolomyte  often  weathers  to  calcareous  sand,  owing  to  a  loss  of  its  cal- 
cite  (the  more  soluble  ingredient)  by  infiltrating  waters. 

c.  Verd-antique,  or  Ophiolyte,  containing  serpentine,  d.  Micaceous. 
e.  Tremolitic ;  contains  bladed  crystallizations  of  tremolite.  f. 
Canaanite  ;  contains  white  pyroxene  in  a  massive  form.  g.  Graphitic  ; 
contains  graphite  in  disseminated  scales,  h.  Chloritic ;  contains 
chlorite,  i.  (Jhondroditic  ;  contains  disseminated  chondrodite  in  large 
or  small  yellow  to  brown  grains. 

White  and  grayish  white  marble  is  abundant  in  western  New  Eng- 
land and  southeastern  New  York  (Westchester  Co.).  The  texture  is 
less  coarsely  crystalline  in  Vermont  than  in  Massachusetts.  Fine  cal- 
cyte  marbles  are  quarried  in  Dorset,  West  Eutland,  Pittsford,  and 
other  places  in  Vermont,  and  statuary  marble  occurs  in  Pittsford. 
In  Vermont,  the  best  quarries  occur  where  the  strata  stand  at  a  high 
angle :  the  layers  were  subjected  to  great  pressure  in  the  upturning 
that  gave  them  this  position,  and  this  pressure  has  soldered  many 
layers  together  that  are  separate  where  the  pressure  was  less  ;  conse- 
quently blocks  as  large  as  an  ordinary  house  might  be  obtained  at 
some  quarries.  Fine  marble  (dolomyte)  is  quarried  at  Lee,  Mass. 
Valuable  marble  exists  also  in  Pennsylvania,  Maryland,  and  Tennes- 
see. The  mottled  reddish  brown  dolomyte  from  East  Tennessee,  and 
mainly  from  Knox  and  Hawkins  counties,  is  a  beautiful  marble  ;  it  is 
a  Lower  Silurian  rock,  and  although  semi-metamorphic,  contains 
ChaBtetes  and  other  fossils.  Another  handsome  marble  is  the  mottled 
red  of  Burlington,  Vt.,  from  the  semi-crystalline  Winooski  dolomyte 
limestone  ;  and  a  still  finer  the  deeper  red  (or  cherry  red),  mottled  and 
veined  with  white,  of  Swanton,  Vt.,  from  the  same  limestone  on  the 
northern  borders  of  the  State,  both  of  the  Cambrian,  and  sometimes 
containing  fossils. 

The  Carrara  marble  of  Italy,  the  Parian,  of  the  island  of  Paros 
(the  birthplace  of  Phidias  and  Praxiteles),  and  the  Pentelican,  from 
quarries  near  Athens,  Greece,  are  examples  of  crystalline  calcyte  lime- 
stone. The  Carrara  marble  varies  in  quality  from  coarse  to  true 
statuary  marble,  and  the  best  comes  from  Monte  Crestola  and  Monte 
Sagro.  The  Cipolin  marbles  of  Italy  are  white,  or  nearly  so,  with 
shadings  or  zones  of  green  talc. 

Excellent  quicklime  is  made  of  crystalline  limestone,  whether  it  be 
calcyte  or  dolomyte.  For  a  good  product  perfect  freedom  from  im- 
bedded minerals  is  essential.  It  does  not  afford  hydraulic  lime,  as  a 
trial  at  New  Haven,  Ct.,  with  an  impure  feebly  crystalline  limestone 
of  right  chemical  constitution,  proved  ;  the  impurity  in  that  case  was 
in  the  state  of  mica. 

II.  Fragmental  Rocks,  exclusive  of  Limestones. 

1.  Conglomerate. — A  rock  made  up  of  sand  and  pebbles, 
or  angular  fragments  of  rocks  of  any  kind;  ordinarily  made 
by  the  consolidation  of  a  gravel-bed,  (a)  If  the  pebbles 


462  DESCRIPTIONS  OF   ROCKS. 

are  rounded,  the  conglomerate  is  a  pudding-stone;  (V)  if 
angular,  a  breccia. 

VAKIETIES.—  a.  Siliceous  or  quartzose.  b.  Granitic,  c.  Calcareous. 
d.  Pumiceous.  e.  Basaltic. 

2,  Grit. — A  hard,    siliceous   conglomerate,   called  also 
millstone  grit,  because  used  sometimes  for  millstones. 

3.  Sandstone. — A  rock  made  from  sand,  or  by  the  con- 
solidation of  a  sand-bed. 

VARIETIES. — a.  Siliceous  or  Quartzose;  consisting  chiefly  of  quartz. 

b.  Granitic;    made  of  granitic  material  or  comminuted   granite. 

c.  Micaceous;  containing  much  mica.     d.  Argillaceous;  containing 
much  clay  with  the  sand.     e.  Gritty ;  hard,  and  containing  small 
quartz  pebbles,    f.  Ferruginous  ;  containing  iron-oxide,  and  therefore 
having  a  red  or  yellowish  brown  color,     g.  Concretionary ;  made  up 
of  concretions,    h.  Laminated ;  consisting  of  thin  layers  or  lamina?, 
or  breaking  into  thin  slabs,  a  characteristic  most  prominent  in  argil- 
laceous sandstones,     i.  Friable;  crumbling  in  the  fingers,     j.  Fossil'f- 
erous ;    containing  fossils,     k.  Feldspathic  (Arkose);    consisting   of 
quartz  and  feldspar,  the  latter  in  coarsish,  cleavable  grains ;  arkose 
includes  also  a  feldspathic  quartzyte. 

The  paving-stone  extensively  used  in  New  York  and  the  neighbor- 
ing States  is  a  laminated^  sandstone,  of  the  upper  part  of  the  Hamilton 
group  in  geology,  quarried  just  south  of  Kingston,  and  at  many  other 
places  on  the  west  side  of  the  Hudson  River.  The  rock  is  remarkable 
for  its  very  even  lamination.  In  western  New  York  and  in  Ohio,  the 
Devonian  sandstones,  above  the  Hamilton  group,  together  with  the 
Waverly  group,  afford  a  similar  flag-stone.  The  "brown-stone"  used 
much  in  New  York  and  elsewhere  for  buildings  is  a  dark-red  sand- 
stone from  the  Triassic  formation,  and  is  from  Portland,  Conn.,  on 
the  Connecticut  River,  opposite  Middletown,  where  it  has  been 
quarried  since  the  middle  of  the  17th  century.  A  lighter-colored 
"brown-stone"  or  "free-stone,"  of  the  same  age,  also  much  used  for 
buildings,  comes  from  Newark,  Belleville,  Little  Falls,  and  other 
points  in  Central  New  Jersey.  The  handsome  sandstone  of  light 
olive-green  tint,  much  employed  in  architecture,  is  from  the  Lower 
Carboniferous  group  in  New  Brunswick.  The  soft  white  sandstone, 
in  much  esteem  among  architects  because  so  easily  cut  and  carved, 
comes  from  Ohio  quarries,  in  beds  of  the  Carboniferous;  it  is  mostly 
from  a  bed  about  sixty  feet  thick,  called  the  "  Berea  grit,"  and  is 
obtained  at  Berea  and  Independence  in  Cuyahoga  County,  and  Am- 
herst  in  Lorain  County,  and  elsewhere. 

Pyrite  is  often  present  in  sandstones  used  for  building,  and  has  de- 
faced and  is  destroying  many  a  beautiful  structure  by  its  oxidation, 
and  the  consequent  decay  of  the  rock. 

^  Sandstones  absorb  moisture  most  easily  in  the  direction  of  the  bed- 
ding or  grain,  if  there  is  any  distinct  bedding;  and  hence  the  blocks, 
when  used  for  a  building  or  wall,  should  be  placed  with  the  bedding 
horizontal.  It  is,  further,  the  position  in  which  the  stone  will  stand 
the  greatest  pressure. 


DESCRIPTIONS   OF   ROCKS.  463 

Grindstones  are  made  from  an  even-grained,  rather  friable  sand- 
stone, and  are  of  different  degrees  of  fineness,  according  to  the  work 
to  be  done  by  them;  were  it  not  friable  enough  to  yield  in  the  grind- 
ing, the  stone  would  become  polished  by  the  worn  metal.  Scythestones 
are  of  similar  nature,  but  finer. 

Hard  siliceous  sandstones  and  conglomerates,  occurring  in  regions 
of  metamorphic  rocks,  are  called  "granular  quartz,"  or  quartzyte 
(p.  468). 

A  rock  made  of  sand,  especially  when  not  of  siliceous  material,  is 
often  called  a  sand-rock.  A  calcareous  sand -rock  is  made  of  calcareous 
sand;  it  may  be  pulverized  corals  or  shells,  such  as  forms  and  consti- 
tutes the  beaches  on  shores  off  which  living  corals  and  shells  are 
abundant. 

4.  Shale. — A  soft,  fragile,  argillaceous  rock,  having  an 
uneven,  slaty  structure.     Shales  are  of  gray,  brown,  black, 
dull  greenish,  purplish,  reddish,  and  other  shades.     It  may 
consist  of  clay  and  fine  sand,  or  contain  much  finely  pul- 
verized feldspar.      It  is  fine  mud   consolidated.      Often 
called  slate,  as  the  slates  of  the  coal-formation. 

VARIETIES.— a.  Ordinary,  of  different  colors,  b.  Bituminous  shale, 
or  Carbonaceous  shale  (Brandschiefer  of  the  Germans),  impregnated 
with  coaly  material  and  yielding  mineral  oil,  or  gas,  or  related  bitum- 
inous matters  when  heated,  c.  Alum  shale  ;  impregnated  with  alum 
or  pyrites,  usually  a  crumbling  rock ;  the  alum  proceeds  from  the 
alteration  of  pyrite  or  the  allied  iron  sulphides  (p.  191-192).  Shale 
graduates  into  laminated  sandstone. 

5.  Argillyte,  or  Phyllyte  (Roofing  slate,  Writing  slate). — 
Argillaceous,  slaty,  differing  froin  shale  in  breaking  usually 
into  thin  and  even  slates  or  slabs;  sometimes  thick-lami- 
nated.     Often   graduates   into   hydromica  and    chloritic 
schists,  and  also,  on  the  other  hand,  into  shale.     Often 
called  Clay-slate.     Much  slate  is  Injdromica  schist;  some 
is  fine  hornbkndic  and  epidotic  schist. 

VARIETIES. — a.  Bluish  black,  b.  Tile-red,  c.  Purplish,  d.  Grayish. 
e.  Greenish,  f.  Ferruginous,  g.  Pyritiferous.  h.  Thick-laminated; 
affording  thick  slabs,  instead  of  slates,  i.  Staurolitic.  j.  Ottrelitic. 
k.  Hornblendic;  microscopally  so.  1.  Thick-bedded  and  often  arena- 
ceous (Graywacke);  a  massive  rock,  affording  thick  blocks  or  masses. 

Extensive  quarries  of  slate  exist  in  Vermont  at  Waterford,  Thet- 
ford,  and  Guilford,  in  the  eastern  slate  range  of  the  State;  in  North- 
field  in  the  central  range,  and  in  Castleton  and  elsewhere  in  the 
western  range.  There  are  excellent  quarries  also  in  Maine  and 
Pennsylvania.  The  rock  furnishes  also  thick  slabs  for  various  eco- 
nomical purposes.  A  trial  as  to  water  absorption,  and  a  close  ex- 
amination as  to  the  presence  of  pyrite,  is  required  before  deciding 
that  a  slate  rock  is  fit  for  use,  however  even  its  fissile  structure. 


464  DESCRIPTIONS   OF   ROCKS. 

Kinds  with  a  glossy  surface  are  most  likely  to  be  impervious  to  moist- 
ure, but  they  may  be  too  brittle  for  good  slate. 
Cattinite;  red  clayey  pipestone;  Minnesota. 

6.  Tufa. — A  sand-rock,  conglomerate,  or  shale,  made  from 
comminuted  volcanic  or  other  igneous  rocks,  more  or  less 
altered.    Colors  yellowish  brown,  gray,  brown,  sometimes 
red.    Usually  loose-textured.    Common  in  volcanic  regions. 
The  name,  from  the  Italian  tufo,  is  often  written  in  Eng- 
lish tuff. 

VARIETIES. — a.  TracTiytic  ;  made  of  trachyte,  of  an  ash-gray  color, 
or  of  other  light  shades,  b.  Andesytic ;  made  of  andesyte.  c.  Pumi- 
ceous ;  made  of  fragments  of  pumice,  d.  Basaltic;  made  from 
basic  igneous  rocks,  such  as  doleryte  (trap)  or  basalt;  usually  yellow- 
ish brown  or  brown  in  color,  sometimes  red.  Pozzuolana  is  a  light- 
colored  tufa,  found  in  Italy,  near  Rome,  and  elsewhere ;  it  is  used 
for  making  hydraulic  cement.  Wacke  is  earthy,  brownish,  like. an 
earthy  trap  or  doleryte,  usually  made  of  trappean  or  dolerytic  material 
and  compacted  into  a  soft  rock. 

Much  of  the  "  sandstone"  and  some  shales  of  the  Tertiary  in  the 
Rocky  Mountain  region  (Montana,  Idaho,  Colorado,  Arizona,  etc.) 
are  tufa  (mostly  andesytic  or  trachytic);  and  petrified  trees  and  opal 
have  been  formed  in  it,  as  explained  on  p.  259.  Tufas,  or  "  ash- 
beds,"  occur  among  the  Paleozoic  and  later  beds  of  Great  Britain. 

7.  Sand.     Gravel. — Sand  is  comminuted  rock-material; 
but  common  sand  is  usually  comminuted  quartz,  or  quartz 
and  feldspar,  while  gravel  is  the  same  mixed  with  pebbles 
and  stones.     Sand  often  contains  grains  of  magnetite,  or 
of  garnet,  or  of  other  hard  minerals  existing  in  the  rocks  of 
the  region.     Occasionally  magnetite  or  garnet  is  the  chief 
constituent,  especially  in  the  upper  portions  of  some  sea- 
beaches. 

Volcanic  sand,  or  Peperino,  is  sand  of  volcanic  origin, 
either  the  "cinders"  or  "ashes"  (comminuted lava),  thrown 
upward  from  the  crater  of  a  volcano,  or  lava  rocks  other- 
wise comminuted. 

8.  Green  Sand. — An  olive-green  sand-rock,  friable,  or  not 
much  compacted,  consisting  of  grains  of  glauconite,  with 
more  or  less  sand.     See  p.  329. 

9.  Clay. — Soft,  impalpable,  more  or  less  plastic  material, 
chiefly  aluminous  (kaolinite)  in  composition,  white,  gray, 
yellow,  red  to  brown  in  color,  and  sometimes  black.    Made 
chiefly  from  orthoclase  feldspar,  by  decomposition.     Often 
contains  much  quartz  sand,  and,  if  alkali-bearing,  pulver- 
ized feldspar.     See  Kaolinite,  p.  332. 


DESCRIPTIONS  OF   ROCKS.  465 

VARIETIES. — a.  Kaolin,  purest  unctuous  clay.  b.  Potter's  clay, 
plastic,  free  from  iron ;  mostly  unctuous ;  usually  containing  some 
free  silica.  Pipe-clay  is  similar,  c.  Fire-brick  clay,  the  same;  it  may 
contain  much  sand  without  injury,  as  sand  is  needed  with  the  clay 
for  brick-making,  d.  Ferruginous,  ordinary  brick  clay,  containing 
iron  in  the  state  of  oxide  or  carbonate,  and  consequently  burning 
red,  as  in  making  red  brick,  e.  Containing  iron  in  the  state  of  sili- 
cate (?),  and  then  failing  to  turn  red  on  being  burnt,  as  the  clay  of 
which  the  Milwaukee  brick  are  made.  f.  Alkaline  and  mtrifiable, 
containing  2*5  to  5  per  cent,  of  potash,  or  potash  and  soda,  owing  to 
the  presence  of  unclecomppsed  feldspar,  and  then  not  refractory  enough 
for  pottery  or  fire-brick,  g.  Marly,  containing  some  calcium  car- 
bonate or  ground  shells,  h.  Weak  clay,  containing  too  much  sand 
for  brick-making,  i.  Alum-bearing,  containing  aluminous  sulphates, 
owing  to  the  decomposition  of  iron  sulphides  present,  and  hence  used 
for  making  alum. 

10.  Alluvium.   Silt.   Till. — A  lluvium  is  the  earthy  deposit 
made  by  running  streams  or  lakes,  especially  during  times 
of  flood.     It  constitutes  the  flats  either  side  of  a  stream; 
and  is  usually  in  thin  layers,  varying  in  fineness  or  coarse- 
ness, being  the  result  of  successive  depositions. 

Silt  is  the  same  material  deposited  in  bays  and  harbors, 
where  it  forms  the  muddy  bottoms  and  shores. 

LCBSS  is  a  fine  earthy  deposit,  following  the  courses  of 
valleys  or  streams,  like  alluvium,  but  mostly  without  di- 
vision into  thin  layers.  Usually  contains  some  calcareous 
material  in  concretions.  Occurs  in  elevated  terraces,  along 
the  broad  parts  of  large  valleys,  as  the  Rhine,  Danube, 
the  Hoangho  in  China,  and  on  some  parts  of  the  Mississippi. 

Till  is  the  unstratified  sand,  gravel,  and  stones,  with  more 
or  less  clay,  deposited  by  glaciers ;  called  also  unstratified 
drift. 

Detritus  (from  the  Latin  for  worn)  is  a  general  term 
applied  to  earth,  sand,  alluvium,  silt,  gravel,  because  the 
material  is  derived,  to  a  great  extent,  from  the  wear  of 
rocks  through  disintegrating  agencies,  mutual  attrition  in 
running  water,  and  other  methods. 

Soil  is  a  mixture  of  clay,  quartz,  sand,  and  other  tritu- 
rated rock  material,  along  with  carbonaceous  matters  from 
vegetable  and  animal  decomposition,  and  from  the  last  gets 
its  dark  color  and  also  a  chief  part  of  its  fertility. 

11.  Tripolyte  (Infusorial    Earth). — Resembles    clay    or 
chalk  in   appearance,  but   is  a  little  harsh   between  the 
fingers,  and  scratches  glass  when  rubbed  on  it;  also  occurs 
firm  and  slaty  from  partial  consolidation.     Consists  chiefly 


466  DESCRIPTIONS  OF  BOCKS. 

of  siliceous  shells  of  Diatoms  with  often  tlie  spicules  of 
sponges,  and  is  silica  in  the  opal  state.  Forms  thick 
deposits,  and  is  often  found  in  old  swamps  beneath  the 
peat. 

This  soft  diatomaceous  material  is  sold  in  the  shops  under  the 
name  of  silex,  electro- silicon,  and  polishing  powder ,  and  is  obtained  for 
commerce  in  Maine,  Massachusetts,  Nevada,  California,  etc.  A  bed 
exceeding  fifty  feet  in  thickness  occurs  near  Monterey  in  California  ; 
and  other  large  beds  in  Nevada  near  Virginia  City,  and  elsewhere. 
It  is  used  as  a  polishing  powder;  in  the  manufacture  of  "soluble 
glass  ;"  and,  formerly,  mixed  with  nitro-glycerine  to  make  dynamite. 
Occurs  slaty  at  Bilin,  Prussia  ;  also  hard  or  indurated  in  some  regions, 
from  consolidation  through  infiltrating  waters,  and  thus  graduates,  at 
times,  into  chert  and  opal. 

II.  Crystalline  Rocks,  exclusive  of  Limestones 

In  the  review  of  the  constituent  minerals  of  rocks  it  has 
been  shown  that  orthoclase  and  mica  are  closely  related  in 
composition,  both  being  eminently  potash-bearing  species, 
and  that  mica  has  often  been  derived  from  feldspar  with 
very  little  change  in  the  amount  of  alkali  (pp.  287,  438); 
and  also  that  leucite  is  closely  related  to  the  potash  feld- 
spars and  nephelite  to  the  soda-lime  feldspars.  It  has  also 
been  observed  that  hornblende  and  pyroxene  are  intimately 
related,  they  being  alike  in  chemical  constitution;  that 
hornblende  is  readily  derivable  from  pyroxene  by  paramor- 
phic  change  (pp.  272,  451),  and  that  it  is  chemically  unlike 
biotite  and  other  micas  in  the  usual  absence  of  an  alkali, 
and  in  other  ways.  It  has  further  been  remarked  that 
rocks  are  acidic  or  basic  according  to  the  feldspar  in  their 
constitution,  without  reference  to  the  presence  of  quartz; 
and  that  quartz  in  grains  is  distributed  widely  through 
igneous  and  metamorphic  rocks  as  it  is  through  sedimen- 
tary, and  has  relatively  little  value  as  a  ground  of  distinc- 
tions among  kinds  of  rocks  (p.  438).  It  has  also  been  shown 
that  no  satisfactory  line  can  be  drawn  between  the  kinds 
of  igneous  and  metamorphic  rocks  (p.  446). 

From  these  and  other  considerations  explained,  we  are 
led  to  the  following  arrangement  of  the  crystalline  rocks. 


DESCRIPTIONS  OF   ROCKS.  467 


A.  SILICEOUS  ROCKS,  OR  THOSE  CONSISTING  MAINLY 

OF  SILICA. 

B.  FELDSPAR,  MICA,  LEUCITE,  NEPHELITE,  SODALITE, 

OR  RELATED  ALKALI-BEARING  SPECIES,  A  CHIEF 
CONSTITUENT. 

In  the  subdivisions  1  to  3  a  potash-feldspar  is  a  promi- 
nent constituent;  in  4  leucite,  also  a  potash-bearing  min- 
eral ;  in  5  and  6  a  soda-lime  or  lime  feldspar. 

1.  The  Potash-Feldspar  and    Mica    Series.      Eminently 
alkali-bearing  rocks,  both  the  mica,  whether  muscovite, 
biotite  or  lepidomelane,  and  the  feldspar,  whether  ortho- 
clase  or  microcline,  affording  on  chemical  analysis  much 
potash,  and  the  feldspars  often  also  some  soda.     The  soda- 
feldspar,  albite  or  oligoclase,   is  a  common  accessory  in- 
gredient.    The  series  shades  off  into  »*ock  that  is  chiefly 
feldspar,  and  another  that  is  chiefly  mica;  and  in  these 

.two  extremes  the  amount  of  potash  yielded  is  about  the 
same.  The  mica  sometimes  contains  4  or  5  per  cent,  of 
water,  or  is  a  hydrous  species  (page  335). 

2.  Potash-Feldspar  and  Hornblende  or  Pyroxene  Series. 
Related  to  the  granite  series,  but  contains  the  non-alkaline 
mineral  hornblende  in   place   of  mica,   with    or  without 
quartz.     Transitions  between  the  granite  and  syenyte  rocks 
are  common — a  bed  of  true  mica  schist  often  becoming 
hornblendic,    or  having  alternating  micaceous  and  horn- 
blendic  laminae;  and   so  there  are  similar  transitions  .in 
other  parts  of  the  two  series. 

3.  Potash-Feldspar  and  Nephelite  Rocks,  Hornblendic  or 
not. 

4.  Leucite  Rocks.    Augitic  or  not. 

5.  Soda-lime-Feldspar  and  Mica  Series. 

6.  Soda-lime-Feldspar  Series,  with  or  without  Hornblende 
or  Pyroxene.     The  feldspar  either  of  the  triclinic  species, 
from  albite  to  anorthite. 

C.  SAUSSURITE  ROCKS. 

Saussurite  and  zoisite  are  alike,  as  pointed  out  by  Hunt, 
in  having  high  specific  gravity  (3  and  over),  and  thus  unlike 
the  feldspar  and  scapolite  series  to  which  they  are  related 
in  composition. 


468  DESCRIPTIONS  OF   ROCKS. 

D.  WITHOUT  FELDSPAR,  OR  WITH  VERY  LITTLE. 

1.  Garnet,  Epidote,  and  Tourmaline  Rocks. 

2.  Hornblende,  Pyroxene,  and  Chrysolite  Rocks. 

E.  HYDROUS  MAGNESIAN  AND  ALUMINOUS  ROCKS. 


A.   SILICEOUS  ROCKS. 

1.  Quartzyte,  Granular  Quartz. — A  siliceous  sandstone, 
usually  very  firm,  occurring  in  regions  of  metamorphic 
rocks.  Does  not  differ  essentially  from  the  harder  siliceous 
sandstones  of  other  regions.  Conglomerate  beds  are  some- 
times included.  Sometimes  friable,  passing  to  loose  sand; 
and  flexible  (Itacolumyte). 

VARIETIES. — a.  Massive,  b.  Schistose,  c.  Micaceous,  d.  Hydro- 
micaceous  ;  it  graduating  at  times  into  hydromica  or  mica  schist,  c. 
Feldspathic,  sometimes  por-phyritic  (the  rock  Arkose);  this  variety  oc- 
curs northeast  of  Lenox,  Mass.,  near  the  borders  of  the  towns  of 
Lenox  and  Washington,  and  also  in  Pownal  and  Bennington,  Vt. ; 
when  it  loses  its  feldspar  it  becomes  cellular,  like  buhrstone,  and  in 
this  state  has  been  used  for  millstones;  by  the  presence  also  of  mica 
it  becomes  gneissoid  or  graduates  into  gneiss,  f .  Friable,  g.  Flex- 
ible (itacolumyte) ;  the  rock  occurs  in  the  gold  regions  of  Brazil  and 
N.  Carolina,  h.  Andalusitic ;  containing  andalusite,  as  in  Mt.  Kear- 
sarge.  i.  Tourmalinic ;  containing  tourmaline. 

In  Western  New  England,  in  Vermont  to  the  west  of  the  principal 
ridge  of  the  Green  Mountains,  and  in  Berkshire  Co.,  Mass.,  and 
Canaan,  Ct.,  in  strata  of  great  thickness,  also  between  Bernardston, 
Mass.,  and  Vernon,  Vt. ;  in  the  central  part  of  New  Hampshire;  in  the 
Archaean  area  of  Wisconsin,  and  in  the  Rocky  Mountain  region.  It 
occurs  friable,  and  as  sand  (used  for  glass-making),  in  Cheshire,  Savoy, 
and  Washington,  in  Berkshire  Co.,  Mass. 

j.  Novaculitic-quartzyte,  or  Novaculyte  ( WJietstone).  Novaculyte,  in 
part,  is  an  extremely  fine  grained  siliceous  rock.  Of  this  nature  is 
the  variety  from  Whetstone  or  Hot  Spring  Ridge,  in  Arkansas.  This 
ridge,  250  feet  in  height  above  the  Hot  Spring  Valley,  is  made  up  of 
the  beautiful  rock,  "  equal,"  says  D.  D.  Owen,  "in  whiteness,  close- 
ness of  texture,  and  subdued  waxy  lustre,  to  the  most  compact  forms 
and  whitest  varieties  of  Carrara  marble.  Yet  it  belongs  to  the  age  of 
the  millstone  grit."  Dr.  Owen  supposed  it  to  have  received  its  impal- 
pable fineness  through  the  action  of  the  hot  waters  on  sandstone.  An 
analysis  of  the  rock  afforded  him  (Second  Rep.  Geol.  Arkansas,  1860, 
p.  24),  Silica  98 '0,  alumina  0'8,  potash  0'6,  soda  0'5,  moisture,  with 
traces  of  lime,  magnesia,  and  fluorine  O'l  —  100.  He  states  that  along 
the  southern  flank  of  the  ridge  there  are  over  forty  hot  springs,  hav- 
ing a  temperature  of  100°  F.  to  148°  F.  Solid  masses  from  the  fine 
rock  have  been  got  out  weighing  about  1,200  Ibs. 


DESCRIPTIONS   OF   KOCKS.  469 

2.  Siliceous  Slate.     (Plithanite.) — Schistose,  flinty,  not 
distinctly  granular  in  texture.     Sometimes  micaceous,  and 
thus  graduates  into  mica  or  hydromica  schist. 

3.  Chert. — An  impure  flint  or  hornstone  occurring  in 
beds  or  nodules  in  some  stratified  rocks.     Often  resembles 
felsyte,  but  is  infusible.    Colors  various.    Sometimes  oolit- 
ic.    Kinds  containing  iron  oxide  graduate  into  jasper  and 
clay-ironstone;  and  others,  occurring  as  layers  or  nodules 
in  limestone,  are  whitish,  owing  to  the  limestone  material 
they  contain.     Chert   sometimes    contains  cavities  which 
are  lined  with  chalcedony  or  agate,  or  with  quartz  crystals, 
making  what  are  called  geodes. 

4.  Jasper  rock. — Dull   red,  yellow,  brown,  or   greenish 
color,  or  of  some  other  dark  shade,  breaking  with  a  smooth 
surface  like  flint.     Consists  of  quartz,  with  more  or  less 
iron  oxide  as  coloring  matter;  the  red  contains  the  oxide 
in  an  anhydrous  state,  the  yellow  in  a  hydrous;  on  heating 
the  latter  it  turns  red. 

5.  Buhrstone. — Cellular  siliceous,  flint-like  in  texture. 
Found    mostly  in    connection  with   Tertiary  rocks,  and 
formed  apparently  from  the  action  of  siliceous  solutions  on 
preexisting  fossiliferous  beds,  the  solutions  removing  the 
fossils  and  leaving  cavities. 

Buhrstone  is  the  material  preferred  for  millstones.  The  buhrstone 
of  the  vicinity  of  Paris,  France,  has  long  been  largely  exported  for 
this  purpose.  Buhrstone  is  reported  from  the  Tertiary  in  Greenville 
District,  South  Carolina,  100  miles  up  the  Savannah  River. 

6.  Fioryte.     (Siliceous  Sinter,  Pearl  Sinter,  Geyseritc.) 
— Opal-silica,  in  compact,  porous,  or  concretionary  forms, 
often  pearly  in  lustre.     Deposited  from  hot  siliceous  waters, 
as  about  geysers  ( Geyserite),  and  made  in  other  ways. 

Geyserite  is  abundant  in  Yellowstone  Park,  and  about  the  Iceland 
and  New  Zealand  geysers.  See  Opal,  p.  261. 

B.  CONTAIN  AS  A  CHIEF  CONSTITUENT  EITHER  A 
FELDSPAR,  MICA,  LETTCITE,  NEPHELITE,  SODA- 
LITE,  OR  A  RELATED  ALKALI-BEARING  SPECIES. 

I.  POTASH-FELDSPAR  AND  MICA  SERIES. 

Besides  rocks  consisting  of  orthoclase  (or  microcline), 
mica,  and  quartz,  others  are  here  included  containing  but 
two  of  these  ingredients;  and  also  those  consisting  chiefly 


470  DESCRIPTIONS  OF   BOOKS. 

of  orthoclase  or  of  mica,  as  part  of  mica  schist  and  much 
hydromica  schist.  Mica  in  many  such  rocks  has  been 
made  from  feldspar  (p.  452). 

1.  Granite.— Orthoclase  (or  microcline),  mica,  and  quartz; 
massive,  with  no  appearance  of  layers  in  the  arrangement 
of  the  mica  or  other  ingredients.  G.  =  2*5-2*8.  The 
quartz  usually  grayish  white  or  smoky,  glassy  (and  distin- 
guished by  absence,  of  cleavage)',  the  feldspar  commonly 
whitish  or  flesh-colored,  its  cleavage  surfaces  usually  dis- 
tinct and  brilliant  in  the  sun-light;  the  mica  in  bright 
scales,  either  whitish  (muscovite),  or  black  (biotite,  or,  at 
times,  some  more  iron-bearing  species).  Oligoclase  or  al- 
bite  often  present,  and  usually  of  whiter  color  than  the 
orthoclase. 

Both  eruptive  and  metamorphic.  Metamorphic  granite 
often  graduates  into,  or  alternates  with,  gneiss. 

VARIETIES. — A.  Muscovite  granite;  B."  Muscovite-and-biotite  gran- 
ite, the  most  common  kind;  C.  Biotite  granite  (granityte);  D.  Hydromi- 
ca-granite. 

a.  Common  or  Ordinary  granite;  col  or  grayish  or  flesh- colored,  accord- 
ing as  the  feldspar  is  white  or  reddish,  and  dark  gray  when  much  black 
mica  is  present.  Granite  varies  in  texture  from  fine  and  even,  to  coarse; 
and  that  of  granite  veins  has  often  the  mica,  feldspar,  and  quartz — 
especially  the  two  former — in  large  crystalline  masses.  An  average 
granite  (mean  of  11  analyses  of  Leinster  granite,  by  Haughton)  affords 
Silica  72'07,  alumina  14*81,  iron  protoxide  and  sesquioxide  2'52,  lime 
1-63,  magnesia  0'33,  potash  5'11,  soda  2'79,  water  1'09  =  100'35.  b. 
Porphyritic;  orthophyric,  and  either  (a)  small  porphyritic,  or  (ft)  large 
porphyritic,  and  the  base  (y)  coarse  granular,  or  (<5)  fine,  and  even 
subaphanitic.  c.  Albitic;  contains  some  albite,  which  is  usually  white, 
d.  Oligoelase  granite  (Miarolyte);  contains  much  oligoclase.  e.  Micro- 
cline granite;  contains  the  potash  triclinic  feldspar,  microcline.  f . 
Hornblendiv;  contains  black  or  greenish  black  hornblende,  along  with 
the  other  constituents  of  granite,  g.  Black  micaceous;  consists  largely 
of  mica,  with  defined  crystals  of  feldspar  (porphyritic),  and  but  little 
quartz,  h.  CJiloritic.  i.  Zirconitic;  containing  zircons,  j.  lolitic;  con- 
taining iolite.  k.  Spherophyric;  containing  concretions  consisting 
chiefly  of  mica  (as  at  Craftsbury,  Vt.,  where  it  is  called  pudding-gran- 
ite). 1.  Gneissoid;  a  granite  in  which  there  are  traces  of  stratification; 
graduates  into  gneiss,  m.  Microgranite;  having  a  very  fine-grained 
base  in  which  mica  exists  with  feldspar,  the  latter  often  in  defined 
crystals;  when  quartzophyric,  it  is  one  of  the  kinds  of  Quartz-porphyry, 
a  kind  of  rock  occurring  at  the  junction  of  granite  and  an  andalusite- 
hydromica  schist  on  the  west  side  of  Mt.  Willard,  near  Crawford's, 
White  Mountain  Notch.  For  muscovite-granites  the  name  Pegmatyte 
was  used  by  Naumann,  perverting  it  from  its  original  use. 

The  following  are  prominent  regions  of  granite  quarries.  In 
Maine-  at  Hallowell,  a  whitish  granite,  sometimes  a  little  gneissoid;  at 


DESCRIPTIONS   OF   HOCKS.  471 

Rockport,  whitish;  at  Clarke's  Island,  spotted  gray;  at  Jonesbury, 
flesh-red;  also  in  the  Mt.  Desert  region.  In  New  Hampshire,  at  vari- 
rious  places,  but  most  prominently  near  Concord,  a  fine-grained  whitish 
granite.  In  Massachusetts  at  several  points,  especially  in  Gloucester 
at  Rockport,  a  red  granite.  (For  Quincy  "  granite"  see  Syenyte.)  In 
Rhode  Island,  at  Westerly,  a  fine-grained  whitish  granite.  In  Con- 
necticut, at  Millstone  Point,  near  Niantic,  and  at  Groton,  near  New 
London,  a  fine-grained  whitish  granite;  at  Stony  Creek,  a  pale  reddish 
and  cream-colored,  but  liable  to  large  micaceous  spots;  at  Plymouth, 
on  the  Naugatuck,  a  whitish  granite,  even  and  fine-grained,  more 
easily  worked  than  the  Westerly.  Aberdeen,  Scotland,  affords  the 
handsome  red  granite  much  used  for  monuments  and  in  architecture; 
also  Peterhead,  Scotland. 

2.  Gramilyte.      (Micaless  granite,   Aplyte,  Weiss-stein, 
Pegmatyte.) — Consists  of  orthoclase  and  quartz,  with   no 
mica  or  Very  little;  often  contains  some  albite  or  oligoclase 
and  garnets.     Coarse  to  line-grained.     White  to  flesh-red. 
G.  =  2*6-2*7.     Silica  70  to  80  p.  c.     Sometimes  schistose. 
Metamorphic  or  eruptive. 

VARIETIES.— a.  Common  granulyte;  white  and  usually  fine  granular; 
occurs  in  Saxony,  Bohemia,  Moravia,  usually  containing  small  gar- 
nets; also  in  Western  Connecticut  and  Westchester  Co.,  New  York; 
at  Rye,  N.  H. ,  containing  very  little  quartz,  b.  Flesh-colored;  usually 
coarsely  crystalline,  granular,  and  flesh-colored ;  a  coarse  flesh-colored 
"  granite"  of  the  Eastern  or  Front  Range  of  the  Rocky  Mts.,  in  Colo- 
rado; it  contains  a  little  albite  or  oligoclase  with  the  orthoclase.  c. 
Garnetiferous.  d.  Horriblendic;  containing  a  little  hornblende — a 
variety  that  graduates  into  syenyte.  e.  Magnetitic;  containing  dissem- 
inated grains  of  magnetite,  a  kind  common  in  Archaean  regions,  in  the 
vicinity  of  the  iron-ore  beds,  occurring  in  Orange  Co.,  N.  Y.,  and 
south  in  New  Jersey,  and  also  at  Brewster's,  Dutchess  Co. ,  N.  Y. ,  and 
in  Kent  and  Cornwall,  Conn,  f .  Grapliic;  quartzophyric  (Pegmatyte), 
the  quartz  looking  like  Persian  cuneiform  characters  over  the  cleav- 
age surface  of  coarsely  crystallized  feldspar,  g.  Microgranulyte;  fine- 
grained, often  orthophyric  or  quartzophyric  (making  one  kind  of 
quartz -porphyry,  called  also  M'icropegmatyte),  found  in  the  Vosges. 

Eruptive  granulyte  has  been  shown  by  Lehman  to  be  sometimes 
schistose  as  a  consequence  of  pressure.  The  name  pegmatite  was  ap- 
plied by  Haiiy  to  graphic  granulyte  from  the  Greek  pegma,  joined 
together,  alluding  to  the  quartz  in  the  feldspar. 

3.  Gneiss. — Like    granite   in    constituents,   colors,   and 
specific  gravity,  but  the  ingredients  arranged  more  or  less 
in  layers,  and  hence  schistose;  varying  from  feebly  schistose, 
or  granitoid,  to  strongly  so,  the  latter  easily  dividing  into 
slabs.     Usually  metamorphic. 

VARIETIES. — a.  Granitoid;  often  graduating  into  granite,  b. 
Strongly  schistose  and  micaceous,  c.  Muscovite  gneiss;  not  common. 


472  DESCRIPTIONS   OF  ROCKS. 

d.  Muscovite-biotife  gneiss,  e.  Biotite  gneiss,  f.  Albitie.  g.  Oligo- 
clastic.  h.  Horriblendic;  containing  hornblende  as  well  as  Motile. 
i.  Epidotic.  .].  Garnetiferous.  k.  Andalusitic.  1.  Gyanitic.  m.  Fibro- 
litic;  containing  fibrolite.  n.  Quartzose;  containing  much  quartz,  o. 
Quartzytic;  consisting  largely  of  quartz  in  grains  and  graduating  toward 
quartzyte,  as  in  Berkshire,  Mass.  p.  Porphyritic;  orthophyric,  Fig.  3, 
p.  440,  porph.  gneiss  of  Birmingham,  Ct.  q.  Spherophyric;  containing 
concretions  of  mica  or  feldspar  and  mica.  r.  Quartzophyric;  contain- 
ing quartz  in  defined  crystals  in  a  fine-grained  base,  and  sometimes 
orthophyric  also,  a  kind  of  quartz-porphyry  called  also  Porphyroid 
and  Hyalopkyre,  found  intercalated  among  stratified  beds  in  the  Ar- 
dennes. 

4.  Greisen. — Massive,  without    schistose   structure.     A 
compact  micaceous  quartz  rock.     The  mica  may  be  mus- 
covite,  lepidolite,  or  biotite.     Occurs  in  regions  of  gneiss, 
granite,  or  quartzyte,  and  sometimes  graduates  into  these 
rocks.     Metamorphic.     Also  called  Hyalomicte. 

Occurs  in  characteristic  form  at  Zinnwald,  in  the  Erzgebirge,  where 
it  sometimes  contains  tin  ore  as  an  accessory  ingredient,  and  is  fre- 
quently penetrated  by  veins  of  tin;  also  in  the  tin  ore  regions  of 
Schlackenwald  and  Cornwall.  Occurs  in  the  region  of  quartzyte, 
hornblendic  rocks  and  gneiss,  of  Upper  Silurian  or  Devonian  age, 
between  Bernardston,  Mass.,  and  Vernon,  Vt.,  within  three  miles 
northeast  of  the  former  place;  and  also  near  Vernon,  but  at  this  place 
it  contains  usually  a  little  hornblende,  making  it  a  very  tough  rock, 
and  is  intermediate  between  the  quartzyte,  hornblendic  rock,  and  mica 
schist  of  the  region. 

5.  Protogine,    Protogine-gneiss. — Coarse  to  fine  granular, 
granite-like  or  gneissoid  in  structure,  and  mostly  the  latter; 
grayish  white  to  greenish  gray;  consists  of  quartz,  white  or 
grayish  white,  rarely  flesh-red  orthoclase,  a  dark  green  mica, 
and  often  chlorite,  with  some  greenish  white  hydrous  mica 
and  white  oligoclase.     Metamorphic. 

The  dark  green  mica  approaches  chlorite,  as  shown  by  Delesse,  in 
its  very  large  percentage  of  iron  oxide  (Fe2O3  21 '31,  FeO  5*03),  but  it 
gave  him  only  0'90  of  water,  with  6  05  of  potash.  Among  accessory 
minerals  are  hornblende,  titanite,  garnet,  serpentine,  magnetite.  In 
an  analysis  of  the  protogine  as  a  whole,  Delesse  obtained  Silica  74 '25, 
alumina  11 '58,  iron  oxide  2 '41,  lime  1'08,  water  0'97,  leaving  lO'Ol 
for  potash,  soda,  and  magnesia.  From  the  region  of  Mont  Blanc  and 
other  parts  of  the  Swiss  Alps. 

At  Littleton,  N.  H.,  a  granite  occurs  consisting  of  orthoclase,  chlor- 
ite, and  quartz,  with  a  little  hornblende;  at  Lancaster,  it  is  orthophyric; 
at  Lebanon,  it  is  a  green  spotted  rock  with  some  scales  of  biotite,  in- 
dicating that  this  mineral  is  the  source  of  the  chlorite;  at  Wallin's 
quarry,  N.  H.,  is  an  epidotic  variety. 


DESCRIPTIONS   OF   ROCKS.  473 

6.  Minette.   Ortholyte.    (Mica-syenyte.) — Gray  to  brown; 
fine-grained,  compact,  massive.    Consists  of  orthoclase  with 
much  mica,  and  a  little  hornblende,  with  some  apatite  and 
magnetite;  sometimes  porphyritic.     Silica  50  to  65  p.  c. 
Metamorphic  ? 

From  the  Vosgcs,  near  Framont,  where  it  occurs  in  beds;  also  in 
Saxony.  The  name  Ortholyte  is  adopted  on  the  geological  map  of 
France.  Approaches  kersantyte,  which  is  a  plagioclase-mica  rock. 

7.  Mica  Schist. — Mica,  with  usually  much  quartz,  some 
feldspar.     On  account  of  the  mica,  usually  thin  schistose. 
The  schist  either  muscovite  schist  or  biotite  schist;  the  lat- 
ter much  the  more  common;  or  contains  both  micas,  which 
is  the  most  common. 

Colors  silvery  to  black,  according  to  the  mica  present; 
often  crumbles  easily;  and  road-sides  sometimes  spangled 
with  the  scales.  The  disseminated  scales  or  crystals  of 
biotite  sometimes  set  transversely  to  the  bedding.  Meta- 
morphic. 

VARIETIES.— a.  Ordinary  ;  coarse  or  fine,  and  various  in  color  and 
constitution  according  to  the  kind  of  mica  present  or  most  abundant, 
b.  Gneissoid;  between  mica  schist  and  gneiss,  and  containing  much 
feldspar,  the  two  rocks  shading  into  one  another,  c.  Horriblendic. 
d.  Garnetiferous.  e.  Staurolitic.  f.  Cyanitic.  g.  Andalusitic.  h. 
Fibrolitic  ;  containing  flbrolite.  i.  Tourmalinic.  j.  Ottrelitie.  k. 
Calcareous;  limestone  occurring  in  it  in  occasional  beds  or  masses. 
1.  Graphitic  (or  Plumbaginous)  ^.the  graphite  being  either  in  scales  or 
impregnating  generally  the  schist,  m.  Quartzose ;  consisting  largely 
of  quartz,  n.  Quartzytic;  a  quartzyte  with  much  mica,  rendering  it 
schistose. 

o.  Specular  schist,  or  Itdbyrite;  containing  much  hematite  or  specu- 
lar iron  in  bright  metallic  lamella  or  scales. 

8.  Hydro-mica  Schist, — Thin  schistose,   and    consisting 
either  chiefly  of  hydrous  mica,  or  of  this  mica  with  more  or 
less  quartz;  the  surface  nearly  smooth;  feeling  greasy  to  the 
fingers,  like  talc;  pearly  to  faintly  glistening  in  lustre; 
whitish,  grayish,  pale  greenish,  and  also  of  darker  shades. 
Metamorphic. 

This  rock  used  to  be  called  talcose  slate  and  magnesian  slate,  but  it 
contains  no  talc.  It  includes  Parophite  schist,  Damourite  slate  and 
Sericite  slate  (Glanz-Schiefer  and  Sericit-Schiefer  of  the  Germans). 
Much,  argillyte  or  roofing  slate  is  here  included,  as  first  shown  by  Sorby. 

VARIETIES. — a.  Ordinary;  more  or  less  silvery  in  lustre,  b.  Chlo- 
ritic;  contains  chlorite,  and  has  sometimes  spots  of  olive-green  color, 
as  in  Orange,  east  of  N.  Haven,  Ct. ,  and  in  the  Taconic  Range  on  the 


4:74  DESCRIPTIONS  OF   ROCKS. 

western  boundary  of  Massachusetts;  graduates  into  chlorite  schist,  c. 
Garnetiferow.  d.  Pyriiiferous;  contains  pyrite  in  disseminated  grains 
or  crystals,  e.  Magnetitic;  contains  disseminated  magnetite,  f.  Quart- 
zytic;  consists  largely  of  quartzyte,  which  is  thus  rendered  schistose. 

A  variety  of  hydromica  schist  (but  called  argillyte},  from  the  White 
Mountain  Notch,  containing  andalusite,  afforded  Dr.  Hawes  Silica 
46'01,  alumina  30'56,  iron  sesquioxide  1'44,  iron  protoxide  6'85,  man- 
ganese protoxide  O'lO,  magnesia  r 42,  soda  1-12,  potash  6*66,  titanium 
dioxide  1'93,  water  413  =  100  "22,  which  is  near  the  composition  of  a 
mica.  (N.  Hampshire  Geol.  Rep.,  ii.  233.)  Another,  from  Wood- 
ville,  N.  H.,  afforded  Hawes  Silica  60'49,  alumina  19'35,  Fe2O3  0'48, 
FeO  5'98,  lime  1*08,  magnesia  2 '89,  soda  2 '55,  potash  3 '44,  water 
3'66  =  99'92.  This  slate,  as  he  recognizes,  is  chemically  like  granite  ; 
but,  by  the  microscopic  study  of  thin  slices,  he  found  it  to  consist  of 
mica  and  quartz,  with  probably  some  feldspar  and  chlorite.  The 
close  relation  in  ultimate  composition  between  the  extremes  of  the 
granite  series,  granite  and  some  argillyte,  is  here  well  illustrated.  All 
the  difference  that  exists  may  be  due  simply  to  difference  in  grade 
and  conditions  of  metamorphism. 

9.  Agalmatolyte.    (Gieseckite,  1813;  Dysintrylite,  1852; 
Finite  in  part.) — Aphanitic;  cut  with  a  knife;  composition 
that  of  the  hydrous  mica,  damourite.    Massive.    G.  =  2*75- 
2  '85.     Greenish  gray,  reddish  gray.     Derived  mostly  from 
the  alteration  of  nephelite.    From  Greenland;  China;  Nor- 
way; the  Archaean  of  Lewis  Co.,  N.  Y.     (See  p.  335.) 

10.  Paragonite  Schist. — Consists  largely  of  the  hydrous 
soda  mica  called  paragonite  (p.  290) ;  but  in  other  characters 
much  resembling  hydromica  schist.     Metamorphic. 

11.  Felsyte.    (Euryte,  'Porphyry,  Petrosilex.) — Compact 
orthoclase,  mostly  aphanitic,  with  commonly  more  or  less 
quartz  intimately  mixed ;   often  orthophyric   (and   called 
Porphyry) ;  sometimes  quartzophyric  (Quartz-porphyry}; 
occasionally  spherophyric (Glob uiar porphyry)',  occasionally 
schistose.      Contains  sometimes  oligoclase,  mica,  minute 
apatites,  and  garnets.     Silica  63-81  p.   c.     Colors  white, 
grayish  white,  red,  brownish  red,    brown,  black.     G.  = 
2  '56-2 '68.     Metamorphic  and  eruptive. 

VARIETIES. — a.  Non-porphyritic,  of  various  colors,  b.  Black. 
c.  Orthophyric.  d.  Quartzophyric.  e.  Quartzless ;  colors  various. 
f .  Spherophyric  ;  the  Pyromeride  of  Corsica,  Schneeberg,  and  Regen- 
berg,  in  which  the  concretions  are  large,  and  consist  of  orthoclase  with 
quartz. 

A  gray  porphyritic  felsyte  occurs  in  dikes  at  Albany  and  Mt.  Pleas- 
ant, Groveton  and  Waterville,  N.  H.;  gray  to  red  about  Mt.  Pequaw- 
bet.  A  black  with  "  here  and  there  a  grain  of  quartz"  at  Waterville, 
N.  H.,  affording  only  63 '63  p.  c.  of  silica,  with  nearly  the  constitution 
of  orthoclase.  A  nearly  quartzless  variety  at  Chambly,  Canada  (silica 


DESCRIPTIONS   OF   ROCKS.  475 

67*60  p.  c.).  A  quartzless  felsyte,  red,  locally  at  Waterville  and 
Albany,  N.  H.;  also  in  dikes  in  Montreal  Mtn.,  containing  dawsonite 
(p.  220).  Felsyte  from  Cottonwood  Canon,  W.  Humboldt  Range, 
made  metamorphic  by  King,  afforded  B.  E.  Brewster  Silica  74 '74, 
alumina  14*14,  Fe2O3  0*79,  lime  1*51,  magnesia  0*39,  soda  0*92.  potash 
5'29,  water  T88  =  99*66,  which  is  the  composition  of  a  normal  felsyte. 
The  antique  red  porphyry  ("rosso  antico")  is  a  variety  of  dioryte. 

12.  Porcelanyte.  (Porcelain  Jasper.) — A  baked  clay,  hav- 
ing the  fracture  of  flint,  and  a  gray  to  red  color;  B.B. 
somewhat  fusible  and  thus  differs  from  jasper.     Formed 
by  the  baking  of  clay-beds  that  contain  feldspar.     Such 
clay-beds  are  sometimes  baked  to  a  distance  of  thirty  or 
forty  rods  from  a  trap  dike,  and  over  large  surfaces  by 
burning  coal-beds.     Metamorphic. 

13.  Mica-Trachyte. — Orthoclase  and  black  mica,  with  a 
little  oligoclase,  augite  and  chrysolite,  and  glass  in  the  base. 
Texture  fine-grained  to  compact.      Color  dark    grayish 
green.     Eruptive.     Monte  Catini,  Italy. 

14.  Trachyte.     (Sanidin-trachyte.) — Mainly  orthoclase, 
with  often  disseminated  glassy  tabular  crystals  of  sanidin, 
and  thence  orthophyric  with  sanidin;  oligoclase  often  pres- 
ent; glass  in  the  base  ;  sometimes  spherophyric  ;  often  hav- 
ing small  needles  of  hornblende,  scales  of  biotite,  magnetite, 
microscopic  apatite.     Silica  60  to  64  p.  c.,  but  less  in  kinds 
containing  much  oligoclase  or  hornblende.    G.  =  2 '6-2*65. 
Owing  to  the  angular  forms  of  the  glassy  feldspar  (sani- 
din) and  the   porosity,  has  a  rough  surface  of  fracture, 
whence  the  name  from  the  Greek  trading,  rough.     Color 
ash-gray,  greenish,  bluish  to  brownish  gray,  rarely  reddish. 
G.  —  2*6-1  •?.    Accessory  minerals,  besides  those  mentioned, 
augite,  nepheline,  haiiynite,  tridymite.    Sometimes  augito- 
phyric.    Graduates  into  quartz-trachyte  or  rhyolyte.    Erup- 
tive. 

VARIETIES. — a.  Plain  trachyte,  b.  Orthophyric,  the  sanidin  crystals 
small  or  large,  c.  Oligoclase  bearing  (Domyte),  and  sometimes  oligo- 
phyric.  d.  Hornblendic  under  each  of  the  above  varieties,  e.  Spar- 
ingly micaceous,  under  each.  f.  Augitic,  and  sometimes  augitophyric, 
graduating  toward  augite-andesyte.  g.  Containing  pyrope.  h.  Vesicu- 
lar, passing  into  a  trachytic  lava  and  pumice. 

Common  in  eruptive  regions  of  Hungary,  Italy,  and  many  other 
parts  of  Europe.  A  kind  from  Ischia  afforded  Silica  61*49,  alumina 
20'02;  Fe2O3  3*11,  FeO  2'72,  MnO  0*01,  magnesia  0*52,  lime  1*88, 
soda  3'39,  potash  7*13,  phosphoric  acid  0*02,  ign.  0*46  —  100*75. 
The  trachyte  of  the  Drachenfels,  near  Bonn,  contains  oligoclase,  and 
is  porphyritic  with  large  crystals  of  sanidin ;  contains  also  some 


476  DESCRIPTION'S  OF  ROCKS. 

needles  of  hornblende,  a  little  augite.  Oligoclase-trachyte  (domite) 
occurs  also  in  the  Puy  de  Dome,  the  Euganean  Hills  (Northern  Italy), 
the  Siebengebirge,  Eifel.  Not  common  in  western  N.  America, 
rhyolyte  (quartz  trachyte)  usually  having  its  place. 

15.  Rhyolyte  or  Quartz-trachyte.    (Liparyte.) — Like  the 
preceding  trachyte  in  its  rough  surface  of  fracture,  color, 
and  more  or  less  glassy,  nuidal  base,  with  frequently  sani- 
din  crystals ;   but   contains  quartz,  and  is  often  quartzo- 

Ehyric  ;  occasionally  spheropnyric.  Coarsely  crystalline  to 
ne-grained  and  glassy;  also  scoriaceous.  Often  contains 
some  oligoclase,  hornblende  in  needles,  black  mica ;  and 
sometimes  tridymite  and  topaz  in  cavities.  G.  =  2 '33-2 '64. 
Colors  light  to  dark  gray,  reddish,  yellow,  brown;  and 
black.  Silica  70  to  82  p.  c. ;  a  kind  from  McKinney's  Pass, 
Nevada,  afforded  Woodward  Silica  74*00,  alumina  11-93, 
Fe203  2-48,  lime  1-56,  soda  2 '64,  potash  5 -65,  water  T24  = 
99  50;  G.  =  2'33. 

VARIETIES. — Those  of  trachyte;  with  also:  h.  Coarsely  porphyritic, 
and  almost  granitoid  (Nevadite);  i.  Quartzophyric,  one  of  the  various 
kinds  of  quartz-porphyry.  Graduating  toward  and  into  obsidian 
through  Pearlyte  and  Pitchstone. 

j.  Pearlyte  (Pearlstone,  Lithoidal  Khyolyte^  has  a  pearly  lustre, 
often  enamel-like  ;  silica  70  to  80  p.  c.  G.  =  2 '35-2  50  ;  usually 
sphcrophyric,  the  spherulites  consisting  of  orthoclase  with  quartz, 
silica  constituting  about  85  p.  c. 

Rhyolyte  is  more  common  than  trachyte,  and  occurs  in  the  same  and 
other  regions.  Common  in  Hungary,  the  Siebengebirge;  the  southern 
of  the  Lipari  Islands;  Iceland.  Abundant  in  Nevada  and  the  rest  of 
the  Great  Basin  between  the  Sierra  Nevada  and  the  Wasatch ;  the 
Yellowstone  Park.  (Hague  and  Iddings,  Am.  J.  Sci. ,  xxvii. ,  453, 1884.) 

16.  Obsidian.    (  Volcanic  Glass.) — True  glass,  but  more  or 
less  microlitic.     Colors  gray,  dull  greenish,  purplish  to  red, 
brown,  and  black.    By  increase  of  microlites  becomes  Pitch- 
stone  (Retinite).    Sometimes  orthophyric,  chrysolitic,  often 
spherophyric.     G.  =  2 -3-2 '5:     Contains  70  to  75  p.  c.  of 
silica,   and   has  essentially  the   constitution  of  rhyolyte 
Pumice  is  a  finely  scoriaceous  variety  with  linear  cells,  con- 
taining 70  to  78  p.  c.  of  silica. 

VARIETIES. — a.  Glass-like  in  aspect,  and  splinters  transparent,  b. 
Semi-lithoidal,  pitch-like  in  lustre  (Pitchstone).  c.  Spherophyric. 
d.  PorpJiyritic  (Vitrophyre).  e.  ChrysopTiyric.  f.  Pumiceous  (Pumice}. 

Obsidian  occurs  with  rhyolyte,  in  Hungary,  the  Lipari  Islands,  in 
Mexico,  etc.  In  the  N.  W.  part  of  the  Yellowstone  Park,  N.  of  Beaver 
Lake,  there  is  a  high  bluff  of  it  capped  by  pumice;  also  a  large  area 
50  miles  east  of  the  bluff ;  the  glass  contains  large  spherulites,  and 
also  concentric  concretions  with  irregular  cavities  between  the  laminae, 


DESCRIPTIONS  OF  ROCKS.  477 

whose  sides  are  often  lined  with  small  crystals  of  sanidin,  tridymite, 
quartz,  and  occasionally  fayalite  (an  iron  chrysolite);  some  portions 
are  porphyritic.  (Iddings.) 

II.    POTASH  FELDSPAR  AND  HORNBLENDE  OR 
PYROXENE  SERIES. 

1.  Syenyte.     (Syenite  of  Werner.) — Coarse  granitoid  to 
microgranitic;  sometimes  porphyritic.     Consists  of  ortho- 
clase  (often  with  microcline)  and  hornblende,  with  no  quartz 
or  but  little;  also  often  contains  biotite  and  some  oligoclase. 
Silica  58  to  63  p.  c.     G.  =  2-7-2-9.     Colors  gray  to  flesh- 
red  and  dark  gray.    Eruptive;  also  met amorphic? 

VARIETIES.— a.  Ordinary,  b.  OrtJiophync.  c.  Containing  oligocJase. 
d.  Biotitic.  e.  Garnetiferous.  f.  Epidotic.  g.  Pyroxenic.  h.  Zirconif- 
erous.  For  zircon-syenite,  a  kind  containing  elaeolite,  see  p.  478. 

From  Plauerschen  Grunde,  Saxony ;  the  Hartz ;  Norway.  A 
Norwegian  afforded  Kjerulf  Silica  59 '93,  alumina  16  "07,  FeO  8  76, 
lime  4-56,  magnesia  2'08,  potash  2'82,  soda  2'98,  water  0*C3  —  97'82. 
Nearly  all  American  syenite  is  of  the  quartz  bearing  kind.  Werner's 
syenyte  being  (as  says  Zirkel  for  western  America)  "  extremely  rare." 

2.  Quartz-Syenyte.     (Syenyte  of  most  early  geologists. 
Hornblende-granite,  Syenite-granite.') — Granitoid  to  micro- 
granitic;   contains   quartz,    with   the   ingredients   of    the 
above-described  syenyte.     Silica  70  to  80  p.  c.     G.  =  2*7- 
2*85.     Metamorphic  and  eruptive. 

VARIETIES.  Same  as  above.  Rather  common  in  ArchaBan  regions 
in  America,  more  so  than  in  those  of  later  age.  Occurs  at  Quincy, 
Mass.  (S  of  Boston);  red  and  gray,  on  the  coast  from  Salem,  Mass  ,  to 
beyond  Manchester;  red  at  Grenville,  Canada,  containing  little  quartz; 
Barrow  I.,  St.  Lawrence;  Frankenstein  Cliff,  White  Mts,  N.  H ,  etc. 

The  name  Syenite  is  from  the  Egyptian  Syene  (modern  Assouan), 
the  place  of  the  great  quarries  that  afforded  the  red  granite-like  rock 
for  obelisks,  the  lining  of  pyramids,  the  columns  of  temples,  sarcophagi, 
etc. ,  and  where  there  is  an  unfinished  obelisk  in  its  original  position. 
The  rock  is  mostly  a  red  granite,  consisting  of  red  feldspar  (orthoclase 
with  some  oligoclase),  quartz,  and  mica,  but  having  also  some  horn- 
blende in  portions  of  it.  Werner  included  under  the  term  a  horn- 
blende and  orthoclase  rock  free  of  quartz  (that  of  the  Plauerschen 
Grunde),  a  kind  not  occurring  in  the  region  of  Syene— and  this  is  its 
restricted  use  now  in  Germany.  Brongniart  and  ethers  defined  it  from 
the  hornblendic  variety  in  Egypt  as  consisting  of  feldspar,  quartz,  and 
hornblende,  making  the  mica  unessential;  and  this  use  of  the  term 
has  been  common  out  of  Germany. 

3.  Syenyte-gneiss. — Like  gneiss  in  schistose   structure 
and  in  mineral  constitution,  except  that  hornblende  takes 


478  DESCRIPTIONS   OF   ROCKS. 

the  place  of  mica.     Some  biotite  often  present.    Graduates 
into  amphibolyte. 

Common  in  the  Archaean  regions  of  the  Adirondacks;  Canada;  the 
Highlands  of  New  Jersey  and  their  extension  southward  and  north- 
ward, and  also  in  other  Archsean  regions.  It  is  properly  a  schistose 
variety  of  quartz-syenyte,  since  structure  is  not  a  character  of  chief 
importance. 

4.  Augite-syenyte. — Like  syenyte,  but  containing,  with 
the  orthoclase,  pyroxene  in  place  of  hornblende.     Part  of 
the  pyroxene  often  changed  to  hornblende. 

Augite  syenyte  free  from  quartz  occurs  at  Jackson,  N.  H.  (Hawes), 
as  an  eruptive  rock,  the  augite  more  or  less  altered  to  hornblende,  and 
containing  also  biotite,  titanic  iron,  apatite ;  at  Mountain  Pond,  in 
Jackson,  N.  H.;  Little  Ascutney  Mtn.;  in  southern  Norway,  with 
zircon-syenyte  and  graduating  into  it. 

Monzonyte,  from  Monzoni,  is  mentioned  as  a  variety  of  augite- 
syenyte,  in  which  the  augite  is  partly  uraliticj  and  there  is  much 
plagioclase  (oligoclase  to  anorthite),  with  SiO2  48  to  59  p.  cent. ;  it  may 
be  an  orthoclase-bearing  diabase.  Glass  in  the  base.  Eruptive. 

5.  Augite  quartz-syenyte.    ("  Augite-granite") — Similar 
to  the  above,  except  in  the  presence  of  quartz. 

Occurs  in  the  Archsean  region  of  Wisconsin  (Irving,  Yan  Hise),  in 
all  stages  of  gradation  from  the  true  augitic  rock  to  a  hornblendic, 
the  latter  a  result  of  the  alteration  of  the  pyroxene  to  hornblende  ;  also 
in  the  Vosges,  but  containing  more  plagioclase  than  orthoclase. 

The  gneissic  form  of  this  rock  is  far  more  common  in  Wisconsin 
than  the  granitoid  ;  and  it  occurs  also  in  the  Yosges. 

6.  TTnakyte. — Consists  of  reddish  orthoclase  and  quartz, 
with  yellow-green  epidote  in  place  of  hornblende.    Coarsely 
crystalline  to  fine  in  texture.    In  Cocke  Co.,  Tenn.,  on  the 
peaks  "The  Bluff,"  "Walnut  Mtn.,"  and  "Max's  Patch," 
and  also  in  Madison  Co.,  N.  C.  (F.  H.  Bradley,  Am.  J. 
Sci.,  III.,  vii.,  519,  1884). 

III.     POTASH-FELDSPAR  AND  NEPHELITE  ROCKS, 
HORNBLENDIC  OR  NOT. 

1.  Zircon-syenyte. — Like  syenyte,  but  contains  also  elaeo- 
lite,  with  disseminated  zircons;  often  also  aegirine,  arfved- 
sonite,  sodalite,  eudialyte,  eukolite,  titanite,  leucophane, 
etc. 

From  Laurvig,  Brevig,  Fredericksvarn,  etc.,  Norway;  Marblehead 
peninsula,  containing  sodalite. 


DESCRIPTIONS   OF   ROCKS.  479 

2.  Foyayte. — Coarse  crystalline-granular;  also  porphy- 
ritic;  also  aphanitic.    Consists  of  orthoclase,  reddish  brown 
nephelite  (elaeolite)  in  6-sided  prisms  and  hornblende  or 
segyrite,  but  no  zircons;  the  porphyritic  is  orthophyric,  and 
has  a  fine-grained  base. 

From  Mt.  Foya  and  Picota  in  the  Province  Algarve,  in  Portugal; 
also  on  the  east  slope  of  Blue  Mtn.,  N.  J.,  between  Beemersville  and 
Liberty  ville,  where  it  occupies  a  dike  £  m.  wide(B.  K.  Emerson,  1882;. 
Contains  a3girite,  titanite,  sodalite. 

3.  Miascyte. — Granitoid  to  schistose.    Consists  of  micro- 
cline,  elaeolite,  biotite,  with  some  quartz;  often  also  zircon, 
pyrochlore,    monazite,    sodalite,    cancrinite,    etc.     Meta- 
morphic? 

Named,  by  G.  Rose,  from  Miask,  Ilmen  Mts.,  where  it  has  a  wide 
distribution.  Occurs  also  on  Pic  Island,  L.  Superior;  Litchfield, 
Me.,  containing  cancrinite  and  sodalite,  and  lepidomelane  in  place  of 
biotite. 

4.  Ditroyte. — A  coarse  to  fine-grained  rock,  consisting 
of  microcline,  nephelite  (elaeolite),  and  sodalite. 

From  Ditro  in  Eastern  Transylvania,  where  it  is  associated  with 
syenyte  and  mica  schist,  and  lies  between  these  two  rocks. 

5.  Phonolyte.      (Clinkstone.) — Compact;    gray,  grayish 
blue,  brownish  gray;    more  or  less  schistose  or  slaty  in 
structure;  tough,  and  usually  clinking  under  the  hammer, 
like  metal,  when  struck,  whence  the  name.     G.  =  2 '4-2 '7. 
Consists  of  glassy  orthoclase,  with  nephelite  and  some  horn- 
blende.    Sometimes  porphyritic.     Composition  of  the  Bo- 
hemian phonolyte  (G.  Jenzsch) :  Sanidin  (glassy  orthoclase) 
53-55,   nephelite   31*76,   hornblende   9 -34,   titanite  3  -67, 
pyrite  0'04  =  98 '36.    Rarely  amygdaloidal.    Accessory  min- 
erals, oligoclase,  pyroxene,  nosite,  hauynite,  leucite.    Erup- 
tive only. 

Occurs  in  Auvergne;  Brisgau;  Bohemia.  Not  reported  from  N. 
America. 


IV.    LEUCITE  ROCKS,  WITH  OR  WITHOUT  AUGITE. 

Usually  some  sanidin  (orthoclase)  is  present,  and  often 
also  some  nephelite  and  labradorite. 

1.  Amphigenyte.  (Leucitopliyre.) — Consists  of  leucite 
(amphigene),  augite,  more  or  less  glass,  with  often  some 
chrysolite,  nophelite,  sanidin,  labradorite,  brown  mica 


480  DESCRIPTIONS   OF   ROCKS. 

(meroxene);  accessory  minerals,  sodalite,  hauynite,  nosite, 
melanite,  magnetite.  Dark  gray  to  grayish  black;  fine- 
grained to  scoriaceous  and  pumiceous;  often  leucitophyric. 
G.  =  2-5-2'9.  Silica  47-50  p.  c.;  but  50  to  58 '5  with 
much  feldspar. 

VARIETIES. —a.  Fine  grained,  with  the  leucite  in  grains,  b.  Leuci- 
topliyric.  c.  Sanidophyric.  d.  NephelophyriC'.  e.  Hauynophyric- 
(HauynophyrS).  f.  Chrysolitic  (Leucite  basalt),  g.  Scoriaceous.  The 
name  amphigenyte  was  given  50  years  since  to  the  leucite-rock  of  the 
Vesuvian  region  by  Cordier,  and  is  as  good  as  any  of  later  origin. 
Constitutes  for  the  most  part  the  lavas  of  Somma  and  Vesuvius;  also 
at  Capo  di  Bove;  the  Eifel;  the  Albanian  Mts.;  the  Erzgebirge  at 
Bohmish-Wiesenthal,  and  elsewhere.  Not  yet  found  in  America. 

2.  Leucotephrite. — Like  the  above  and  occurring  in  the 
same  regions,  but  containing  much  labradorite. 

3.  Leucityte. — A  grayish  to  greenish  gray  rock  consist- 

ing of  leucite  crystals,  and  having  a  porous 
leucitic  ground-mass,  with  very  little 
angite  and  some  biotite  (the  large  crys- 
tals in  the  figure  annexed);  also  traces  of 
magnetite  and  biotite.  Silica  54*42  p.  c. 

From  Point  of  Rocks,  Wyoming.  An  asso- 
ciated porous  rock  passes  into  a  micaceous 
pumice.  (Figure  from  Zirkel.) 


V.     SODA-LIME-FELDSPAR  AND  MICA  ROCKS. 

Kersantyte.  (Mica-dinryte,  Mica-porpliyrite,  Soda- 
granite,  Hemidioryte.) — Granitoid  to  fine-grained  ;  gray- 
ish to  brown  and  grayish  black.  Chiefly  oligoclase  and 
biotite,  usually  some  quartz,  hornblende,  orthoclase,  mag- 
netite, apatite ;  sometimes  oligophyric.  Silica  53  to  67 
p.  c.  Graduates,  through  the  increase  of  hornblende  and 
loss  of  biotite,  into  dioryte. 

From  the  Vosges,  at  Visembach  and  St.  Marie  ;  porphyritic  varie- 
ties (Mica-porphyrite)  in  Auvergne;  Schwarzwald,  etc.  Granitoid,  at 
Stony  Point,  on  the  Hudson,  and  near  Cruger's,  in  Cortlandt,  N.  Y. 

VI.     SODA-LIME  FELDSPAR   AND    HORNBLENDE  OR 
PYROXENE  ROCKS. 

The  kinds  of  rocks  here  included  differ  chiefly  in  the 
kind  of  triclinic  feldspar  present — the  minerals  horn- 


DESCRIPTIONS   OF   ROCKS.  481 

blende  and  pyroxene  (diallagic  or  not)  having  essentially 
the  same  composition.  One  series  has  oligoclase  as  the 
predominant  feldspar,  and  another  the  more  basic  feld- 
spars, labradorite,  anorthite.  Under  each  there  is  great 
diversity  in  the  kinds  of  rocks  as  to  texture,  for  coarse- 
grained or  granitoid,  fine-grained,  aphanitic,  and  glass- 
bearing  varieties  occur  in  each  series,  and  sometimes  (as 
shown  by  Hague  and  Iddings  from  Nevada  investigations, 
and  by  Judd  and  Lotti)  in  the  same  eruptive  mass.  The 
oligoclase  kinds  often  graduate  into  labradorite,  obscuring 
distinctions,  and  sometimes  also  into  orthoclase  rocks,  as  in 
Wisconsin  (Irving).  The  hornblendic  kinds  have  in  many 
cases  resulted  from  the  alteration  of  thepyroxenic  (p.  451). 
The  name  trap  is  a  common  and  convenient  designation 
of  the  dark-colored  fine-grained  pyroxene  kinds. 

1.  Dioryte.  Quartz-Dioryte.  .  (Greenstone  in  part.) — 
Typical  dioryte  :  chiefly  oligoclase  and  hornblende,  with 
often  some  orthoclase  and  biotite;  chlorite  usually  present 
in  dark  green  varieties,  and  sometimes  epidote.  No  glass 
present.  Texture  granitoid  to  aphanitic  ;  often  porphy- 
ritic  ;  sometimes  spherophyric.  Color  often  grayish  white 
to  greenish  white  for  the  coarser  kinds ;  olive-green  to 
blackish  green  and  red  for  the  finer.  Very  tough.  Silica 
50-64  p.  c.,  when  free  from  quartz.  G.  =  2*66-3-0. 

The  quartz-bearing  and  quartz-less  kinds  constitute  two 
sections  having  similar  varieties.  Dark  red,  brownish  red, 
and  dark  green  porphyritic  kinds,  compact  in  base,  have 
been  called  Porphyry tc.  Metamorphic  and  eruptive. 

VAKIETIES. — a.  Granitoid;  granite-like  in  texture,  b.  Fine- 
grained, c.  Aphanitic.  d.  Oligophyric  (Porphyrite,  Hornblende-por- 


biotite. 

Occurs  in  Saxony,  Thuringia,  Bohemia,  the  Vosges,  and  other 
parts  of  Europe,  and  often  porphyritic;  also  in  Scotland  and  Ireland; 
Mt.  Dokhan,  Egypt  (the  "  rosso-antico);  in  New  York,  on  the  Hud- 
son, north  of  Cruger's,  a  granitoid  kind  having  the  hornblende  prisms 
in  some  places  1-4  in.  long,  and  graduating  into  a  granitoid  kersantytc; 
also  at  Littleton,  Lancaster,  and  Lisbon,  N.  H. ;  W.  and  N.  W.  of 
Baltimore,  where  it  has  been  derived  from  the  alteration  of  "  gabbro" 
(G.  H.  Williams).  A  dioryte  from  the  Hartz  afforded  Silica  54'65, 
alumina  15 "72,  Fe,O3  2 '00,  FeO  6 '26,  MnO  trace,  magnesia  5 '91, 
lime  7'83,  potash  3'79,  soda  2'90,  water  1-90  =  100'96. 

Banatite  and  Tonalite  are  like  quartz-dioryte  in  most  characters. 
31 


482  DESCRIPTIONS   OF   ROCKS. 

Each  contains  some  biotite,  the  latter  much  of  it.  Banatite  is  from 
the  Banat,  and  Tonalite  from  near  Tonale,  in  the  Southern  Alps. 
Hemithrene  is  a  dioryte  containing  calcite  (and  effervescing  with 
acids);  probably  an  altered  dioryte. 

Mica-dioryte.— Dioryte  often  passes  by  a  gradual  disappearance  of 
the  hornblende,  and  the  appearance  of  scales  of  black  mica  (biotite), 
into  the  non-hornblendic  rock  kersantite,  called  also  mica-dioryte. 
See  p.  480. 

2.  Augite-Dioryte. — Containing  augite  with  the  oligoclase, 
and  but  little  hornblende;  the  augite  often  more  or  less 
altered  to  hornblende.     Colors  dark  gray  to  greenish  black 
and   black,  without   any  glass.     Hornblende-dioryte    has 
often  resulted  from  the  alteration  of  augite-dioryte. 

Observed  under  partially  altered  form  by  Wichmann,  Wadsworth, 
and  Irving  in  northern  Michigan  and  Wisconsin;  occurs  also  in  Cort- 
landt,  N.  Y. ,  and  on  Stony  Point,  where  it  is  partly  altered  to  horn- 
blende-dioryte  (G.  H.  Williams). 

Hypersthene-dioryte,  a  rather  fine-grained  rock  containing  hyper- 
sthene  in  place  of  augite,  but  partly  altered  to  hornblende,  occurs  also 
at  Stony  Point  and  in  Cortlandt.  Its  mineral  constitution  is  that  of 
noryte 

Ophyte. — A  greenish  black  fine-grained  to  aphanitic  rock,  often 
schistose,  containing  pyroxene  in  the  form  of  diallage,  with  horn- 
blende and  small  crystals  of  oligoclase,  some  biotite,  chlorite,  epi- 
dote  ,  sometimes  spherophyric.  Common  at  Biarritz  and  elsewhere 
in  the  Pyrenees. 

3.  Labradioryte.    (Lalradorite-dioryte,    Greenstone    in 
part.) — Labradorite  or  anorthite  with  hornblende.     Tex- 
ture usually  fine-grained,   crypto-crystalline  to  aphanitic, 
without  glass.     Color  light  grayish  green  to  dark  olive- 
green,  blackish  green  or  gray,  and  sometimes  black.     Very 
tough.     G.  —  2-8-3 '1.     Often  contains  chlorite  and  mag- 
netite.    Metamorphic  and  eruptive. 

VARIETIES.— a.  Granular  crystalline,    b.  Compact,  or  fine-grained. 

c.  Porphyritic;  the  feldspar  in  whitish  or  greenish  white  crystals  dis- 
seminated through  a  fine-grained  base,  making  a  greenish  "  porphyry." 

d.  Pyroxenic;  containing  some  disseminated  pyroxene,    e.  Magnetitic; 
containing  magnetite  or  titanic  iron.     Occurs  in  the  Urals;  in  Orange, 
west  of  New  Haven,  Conn.,  both  massive  and  porphyritic;  of  black 
color  in  dikes  at  Compton  Falls,  N.  H.  (Hawes).     The  porphyritic 
variety— a  metamorphic  rock — afforded  Hawes,  Silica  48 '61,  alumina 
17 '81,  iron  scsquioxide  0'25,  iron  protoxide  8 '46,  manganese  protoxide 
0'20,  lime  11-16,  magnesia  7'76,  soda  2 '77,  potash  0'47,  water  T63, 
titanium  dioxide  1'35  =  100'47;  G.  =  3'01;  the  crystals  of  the  porphy- 
ritic variety,  according  to  an  incomplete  analysis  by  E.  S.  Dana,  consist 
of  anorthite;  they  are  mostly  altered,  and  probably  in  the  state  of 
saussurite. 

Epidioryte  consists  of  plagioclase  with  hornblende,  some  quartz,  a 


DESCRIPTIONS   OF   ROCKS.  483 

little  orthoclase,  and  some  pyroxene.     Silica  56  p.  c.     Chlorophyre  of 
Quenast,  Belgium,  is  related. 

An  augite-dwryte  containing  Idbradorite  in  place  of  oligoclase  is  iden- 
tical in  mineral  composition  with  gabbro  and  basalt. 

4.  Andesyte.    (Hornblende-andesyte.} — Consists  of  oligo- 
clase or  andesite  and  hornblende,  with  often  some  orthoclase 
or  sanidin,   and  biotite.     Sometimes  porphyritic.      Color 
usually  dark  to  light  green,  and  gray,  sometimes  purplish; 
aspect  more  or  less  trachytic.     Some  glass  in  the  base,  as 
in  lavas.    Silica  59-63  p.  c.    G.  =  2-6-2-7.    Texture  varies 
from   coarsely   crystalline   to    microcrystalline,   trachytic, 
rhyolitic,  glassy,  scoriaceous,  and  at  Washoe,  Nevada,  these 
wide  extremes  exist  in  the  same  eruptive  mass,  according 
to  Hague  and  Iddings. 

5.  Dacyte.      (Quart  z-andesyte.) — Like    the    above,   but 
containing    disseminated   quartz    grains,    and    sometimes 
quartzophyric.     Silica  65  to  70  p.  c.     Often  graduates  into 
the  orthoclase  rock,  rhyolyte. 

VARIETIES  of  Andesyte  and  Dacite. — a.  Fine-grained,  b.  Porphy- 
ritic. c.  Micaceous  (Hornblende  mica-andesyte).  d.  Eypersthenic.  e. 
/Scoriaceous.  f.  For  dacyte,  quartzophyric. 

From  the  Andes  in  Cotopaxi,  Chimborazo,  etc.  Common,  espe- 
cially the  dacyte,  over  the  Great  Basin,  in  Nevada  and  elsewhere, 
and  in  the  volcanoes  of  the  Pacific  border.  Propylyte,  of  Nevada,  is 
altered  andesyte,  as  first  pointed  out  by  Wadsworth. 

Timacyte  is  labraclorite-andesyte,  from  Timokthale,  Bulgaria. 

6.  Augite-Andesyte. — Contains  the  same  feldspars  as  an- 
desyte; but  augite  is  present,  and  often  hypersthene,  in 
place  of  hornblende,  but  often  is  in  part  changed  to  horn- 
blende.    Amount  of  silica  56  to  61  p.  c.,  or  62  to  77  from 
the  presence  of  quartz.     More  or  less  glass  present.     Tex- 
ture  crystalline,  granular  to  aphanitic  and   fluidal;   also 
glassy,  and  resembling  pearlyte  and  obsidian,  and  sphero- 
phyric.     Eruptive. 

VARIETIES. — There  are  two  series:  A.  Ordinary,  that  is,  without 
chrysolite,  or  only  in  traces.  B.  Chrysolitic,  chrysolite  being  in  dis- 
seminated grains  or  crystals.  Under  each  there  are  varieties,  a.  Or- 
dinary, b.  Hornblendic  (Hornblende-avgite-andetyte').  c.  Chloritic, 
containing  disseminated  chlorite  and  feeble  in  lustre,  d.  Amygdaloidal 
(and  chloritic).  e.  Porphyritic,  The  chrysolitic  variety  is  one  of  the 
rocks  that  has  been  called  Melaphyre.  Reported  from  the  Great  Basin, 
but  much  of  the  rock  there  is  hypersthenic,  and  belongs  to  the  follow- 
ing. Trachy-doleryte  is  essentially  augite-andesyte;  a  felsytic  variety 
occurs  among  the  English  Cumberland  lavas. 


484  DESCRIPTIONS   OF   ROCKS. 

7,  Hypersthene-Andesyte. — Like  augite-andesyte,  and 
may  be  considered  a  variety  containing  hypersthene  in 
place  of  most  of  the  augite.  Color  gray,  bluish  gray,  red- 
dish, black.  G.  =  2 -6-2 '7.  Often  por-phyritic.  Some- 
times chrysolitic.  Passes  into  glassy  and  pumiceous  varie- 
ties. 

Constitutes  part  of  the  rock  of  Buffalo  Peaks,  Colorado,  and  of  an- 
desyte  localities  in  the  Great  Basin;  common  rock  at  Mt.  Rainier  and  , 
Mt.  Hood,  Mt.  Shasta,  at  Washoe,  Nevada.     When  chrysolitic,  near 
basalt  in  its  characters. 

8."  Hyperyte.  (Hyperstliene-gablro.  Noryte  in  part.) — 
Granitoid.  Consisting  chiefly  of  labradorite  or  anorthite, 
with  hypersthene,  usually  some  pyroxene;  also  biotite  and 
magnetite;  sometimes,  chrysolitic. 

From  the  Hartz;  Hitteroe",  Egersund,  Norway;  St.  Paul,  coast  of 
Labrador;  West  and  N.  West  of  Baltimore,  Md. 

9.  Gabbro.     Granitoid;  consisting  chiefly  of  labradorite 
and  pyroxene,  often  a  diallagic  variety  ;   often   contains 
some  hornblende ;  also  magnetite  or  ilmenite ;  sometimes 
chrysolitic.     No  glass.     Color  dull   flesh-red  to  brownish 
red  and  dark  gray.     G.  =  2'7-3'l,  varying  with  the  pro- 
portion  of    pyroxene,    which   is   sometimes   small.      The 
chrysolite  is  often  in  part  changed  to  serpentine. 

VARIETIES. — a.  Granitoid,  b.  Feldspathic,  the  amount  of  pyrox- 
ene small,  c.  Chrysolitic  (Ottvine-gabbro),  containing  disseminated 
chrysolite,  which  is  often  more  or  less  changed  to  serpentine,  d. 
Macrocrystalline,  and  thus  graduating  insensibly  into  doleryte  or  basalt. 
Common  in  the  Adirondacks  and  the  Archa3an  of  Canada;  Waterville, 
N.  H.,  where  it  is  chrysolitic,  and  is  associated  with  an  altered  variety 
containing  serpentine;  also  on  Mt.  Washington  River. 

The  name  Gabbro  is  of  Italian  origin.  It  is  now,  and  has  long 
been,  used  in  Italy  for  a  green  serpentine  rock.  Signer  Lotti  says 
(1885)  that  it  is  not  possible  there  to  adopt  the  perverted  use  of  lithol- 
ogy.  Gabbro  rosso  in  Italy  is  a  reddish  altered  gabbro.  The  name 
EupJwtide  in  Italy  covers  a  labradorite  rock  like  the  above  in  mineral 
constitution,  and  also  the  same  in  which  the  labradorite  is  altered  to 
saussurite,  the  former  graduating  into  the  latter. 

10.  Doleryte. — Texture  varying  from  a  rather  fine-grained 
granitoid  to  aphanitic;  often  granulitic  through  the  interior 
of  the  eruptive  mass,  and  aphanitic  and  glass-bearing  along 
the  walls  where  cooled  rapidly;  also  rhyolitic,  and  scoria- 
ceous.      Consists,  like  gabbro,  of  labradorite  and  pyroxene, 
with  the  pyroxene  sometimes  diallagic;  often  porphyritic; 
often  contains  chrysolite  (olivine);  and  magnetite  or  me- 


DESCRIPTIONS   OF   ROCKS.  485 

naccanite  in  minute  grains.  Color  dark  gray  to  grayish 
black,  greenish  black  and  brownish  gray,  black ;  G.  =  2*  75- 
3'1.  Includes  the  most  of  what  is  called  trap.  Chryso- 
litic  kinds  sometimes  altered  to  impure  serpentine. 

VARIETIES. — A.  Diabase.  Granitoid  to  fine-grained  and  aphanitic; 
the  granitoid  variety  essentially  like  gabbro.  Free  from  glass.  Often 
chrysolitic.  Often  chloritic  and  amygdaloidal  (Spilyte).  Often 
labradophyric,  sometimes  anorthophyric.  Often  augitophyric.  Oc- 
casionally contains  quartz.  Graduates  imperceptibly  into  the  fol- 
lowing: 

B.  Basalt.  Granulitic  to  aphanitic  (Aname&yte)  and  scoriaceous. 
Glass  present.  Otherwise  as  above.  Lavas,  stony  and  scoriaceous, 
here  included.  Quartzophyric,  at  Lassen's  Peak  (Diller). 

Abundant  in  most  regions  of  volcanic  and  other  igneous  rocks.  Con- 
stitutes the  trap  ridges  of  the  Connecticut  Valley,  Palisades  on  the  Hud- 
son, and  similar  lidges  in  Nova  Scotia,  Pennsylvania,  Virginia  and  N. 
Carolina,  where  some  are  chloritic  and  amygdaloidal ;  also  covers 
large  areas  over  the  western  slope  of  the  Rocky  Mountains.  An  anor- 
thophyric variety  at  East  Hanover,  N.  H.,  has  anorthite  crystals  \  tof 
in.  broad,  and  same  occurs  also  at  Moose  Mtn.  and  in  Stark,  N.  H. ,  and 
at  Concord,  Vt;  and  with  crystals  $  in.  of  anorthite,  and  distantly 
spaced,  in  the  Buttress  dike  crossing  West  Rock,  Woodbridge,  ancl 
Orange,  near  New  Haven,  Ct.  On  the  use  of  the  term  diabase  see 
p.  445.  Palatinite  is  related  to  the  above. 

The  "  antique  green  porphyry,"  or  Porfido  verde  antico,  figured  on 
page  440,  in  Fig.  2,  is  a  porphyritic  doleryte  or  diabase,  the  feldspar 
being  labradorite,  and  the  other  chief  constituent,  augite,  with  also 
some  chlorite  or  viridite,  which  last  is  the  source  of  the  greenish 
color.  It  is  from  the  South  Morea,  between  Lebetspva  and  Marathpn- 
isi.  Delesse  obtained,  from  the  compact  base,  Silica  53'55,  alumina 
19 '34,  iron  protoxide  7 '35,  manganese  protoxide  0'85,  lime  8 '02,  soda 
and  potash  7 '93,  water  2 '67.  In  view  of  its  firmness,  and  its  contrast 
in  this  respect  with  most  chloritic  doleryte,  it  may  be  queried  whether 
the  rock  is  not  a  metamorpJiic  doleryte.  It  closely  resembles  the  por- 
phyritic labradioryte  from  the  vicinity  of  New  Haven,  Conn  (which 
is  chloritic  and  metamorphic),  though  differing  from  it  in  containing 
pyroxene  instead  of  hornblende.  A  similar  porphyry  is  reported  from 
Elbingerode  in  the  Hartz,  Belfahy  in  the  Vosgcs,  and  Barnetjern  near 
Christiania  in  Norway. 

The  name  Melaphyre  was  first  used  for  a  black  porphyry  described 
ns  having  feldspar  crystals  in  a  compact  hornblendic  base  ;  since,  for 
dark  augite-oligoclase  rocks  (dioryte  or  andesyte),  porphyritic  or  not ; 
compact  augite- labradorite  rocks  (diabase  or  doleryte),  non-porphyrit- 
ic  ;  the  same,  chrysolitic,  and  amygdaloidal  or  not.  Like  anamesyte 
and  spilyte,  it  is  not  needed  in  petrography. 

11.  Tachylyte.  (Hyalomelan. ) — Blackish  glass,  or  pitch- 
stone,  connected  with  augitic  igneous  rocks  or  lavas ;  some- 
times porphyritic;  often  contains  grains  of  augite  or  chrys- 
olite. The  former  affords  on  analysis  55  per  cent,  of 
silica,  and  the  latter  50  to  55. 


486  DESCRIPTIONS   OF   ROCKS. 

Tachylyte  is  from  Sasebiihl,  Germany;  north  shore  of  L.  Superior, 
etc.  ;  Hyalomelan  from  a  volcanic  rock  in  the  Vogelsgebirge.  Sider- 
omelan  is  a  tachylyte  from  Iceland.  Limburgyte  is  an  augitic  glass. 

12.  Eucryte.  —  A  doleryte-like  rock,  consisting  chiefly  of 
anorthite  and  augite,  with  sometimes  chrysolite.     Occurs 
granitoid  to  fine-grained,  and  as  a  lava. 

From  Elfdalen,  Norway;  Puy  de  Dome,  France;  Carlingford,  Ire- 
land, etc. 

Troctolyte  consists  of  anorthite  and  chrysolite,  with  some  augite. 

13.  Corsyte.     (Orbicular  Dior  yte.)  —  Anorthite  and  horn- 
blende with  some  quartz  and  biotite.     Spherophyric,  and 
consisting  chiefly  of  concretions  of  anorthite  and  hornblende 
with  a  little  quartz. 

From  Corsica;  the  Shetlands;  Bohemia;  Yamaska  Mtn.,  Canada. 

14.  Anorthityte.  —  Coarsely  crystalline-granular.  Consists 
largely  of  anorthite,  or  a  feldspar  near  it  in  composition. 
Light  gray  to  white  or  faintly  greenish;  an  occasional  trace 
of  augite  and  chrysolite.     An  analysis  of  the  "  anorthite" 
gave  the  oxygen  ratio  1  :  2*4  :  4'15,  with  about  47  p.  c.  of 
silica,  showing  divergence  from  anorthite  (Irving). 

On  the  N.  shore  of  L.  Superior,  between  Split  Rock  River  and  the 
Great  Palisades,  and  in  Carl  ton's  Peak,  near  the  mouth  of  Temperance 
R.  Eruptive.  (AnortMte-rock  of  Irving  ) 


15.  Nephelinyte.     (Neplieline-doleryte,   Tepliryte.)  — 
phelite  with  augite  and  some  magnetite;  with  or  without 
chrysolite;  often  nephelophyric.     Ash-gray  to  dark  gray. 
Frequent  accessory  minerals,  leucite,  hauynite,  sanidin,  bio- 
tite, hornblende,  etc. 

VARIETIES.  —  a.  Ordinary,  b.  Nephelophyric.  c.  Chrysolitic  (Ne- 
pheline-basalt).  d.  Plagiodase-bearing  (Nepheline-tephryte).  e.  Melir 
litic  (MeliUte-basalt}.  f.  Hauynitic.  g.  Hornblendic  (Buchonite). 

Occurs  at  Katzenbuckel,  in  the  Oderwald,  Eifel,  Schwarzwald, 
etc. 

16.  Teschenyte.  —  Felsytic  in  texture;  dark  bluish  green. 
Consists  chiefly  of  anorthite  or  labradorite,  nephelite,  horn- 
blende, and  augite.     The  hornblende  sometimes  in  large 
black  prisms.     Accessory  minerals  black  mica,  apatite. 

From  Tetschen,  Moravia. 


DESCRIPTIONS   OF   ROCKS.  487 


C.   SATJSSTJBITE  ROCKS. 

Euphotide.  (Gabbro  in  part.)  Grayish  white  to  gray- 
ish green,  and  sometimes  olive-green;  very  tough.  G.  = 
2  '9-3  *4.  Consists  of  saussurite  with  diallage  or  smaragdite; 
the  saussurite  often  accompanied  by  labradorite,  or  other 
triclinic  feldspar;  Silica  43  to  52  p.  cent.  The  saussurite 
probably  altered  labradorite  or  other  triclinic  feldspar,  and 
the  smaragdite  altered  diallage.  Graduates  into  gabbro,  a 
related  rock  in  which  the  labradorite  is  unaltered,  and  also 
into  the  finer  grained  labradorite-rocks  of  similar  constitu- 
tion, diabase  and  basalt ;  in  Italy  both  the  euphotide  and 
gabbro  are  called  euphotide.  Chrysolite  is  often  present, 
as  in  gabbro,  and  also  serpentine  as  a  result  of  the  altera- 
tion of  chiefly  the  chrysolite.  Altered  eruptive  (Lotti). 

VARIETIES. — a.    Diallagic  ;   diallage  the  chief  foliated  mineral. 

b.  Smaragditic ;    emerald-green  smaragdite,  the  foliated  mineral. 

c.  Micaceous;  contains  mica.     d.   Chrysolitic.    e.   Serpentinous.     f. 
Garnetfferous.     g.    Schistose;   especially  when  talc   is  present,    h. 
Spherophyric  ;  contains  aphanitic  concretionary  spheroids  of  the  saus- 
surite  mineral,  as  in  the  "  Variolite  de  la  Durance,"  and  of  Mt. 
Genevre,  and  associated  with  ordinary  euphotide.     The  variety  ob- 
tained at  Orezza  is  the  Verde  di  Corsica,  of  decorative  art. 

Occurs  near  Lake  Geneva,  in  Savoy;  at  Mt.  Genevre  in  Dauphiny, 
near  the  boundary  between  France  and  Italy ;  at  Allevard,  in  the 
northeastern  part  of  Isere;  in  the  valley  of  the  Saas,  north  of  east  of 
the  Monte  Rosa  region  ;  in  the  Orisons  ;  near  Leghorn  and  Bologna  ; 
near  Florence,  at  Mt.  Impruneta;  Corsica,  in  the  Orezza  valley;  Silesia; 
I.  of  Unst. 

D.   ROCKS  WITHOUT  FELDSPAR. 

1.  GARNET,  EPIDOTE,  TOURMALINE  ROCKS. 

1.  Garnetyte.    (Garnet  Rock.)    Massive  fine-grained  gar- 
net.    Color  yellowish  or  buif  to  greenish  white.     Tough. 
G.  =  3-3  to  3-54.    -H.  =  7'0. 

From  Vieil  Salm,  Belgium,  a  manganesian  garnet  (Renarcl),  being 
the  superior  yellowish  novaculite  or  razorstone,  where  it  makes  layers 
in  a  hydromica  (sericite)  schist;  St.  Frai^ois  and  Orford,  Canada,  an 
alumina-lime  garnet  (Hunt). 

2.  Eclogyte,    (Ompliacite.) — Fine-grained  granular  rock, 
consisting  of  red  garnet  in  a  base  of  grass-green  smaragdite, 
with  occasionally  zoisite,  actinolite,  and  mica.    Very  tough. 


488  DESCRIPTIONS   OF   ROCKS. 

Also  essentially  the  same  rock,  of  dark  color,  consisting  of 
reddish  or  brownish  yellow  garnet  with  black  or  greenish 
black  hornblende  and  some  magnetite. 

3.  Epidosyte. — Compact,  pale  green  to  pistachio-green. 
Very  tough  and  hard.     Consists  of  epidote  and  quartz.     A 
variety  from  the  Shickshock  Mts.,  Gaspe,  of  a  pale  yellow- 
ish color,  has  H.  =  7  and  G.  =  3-04-3-09  (Hunt). 

4.  Tourmalyte.     (Schorl  Rock.) — Granular  and  compact 
schistose.     Consists  of  tourmaline  and  quartz,  with  often 
chlorite,  mica,  and  sometimes  tin-ore.     Occurs  massive  in 
Cornwall ;  schistose  at  Eibenstock,  in  Saxony ;  in  Marble 
Mtn.  and  Ragged  Ridge,  Warren  Co.,  N.  J.  (G..H.  Cook). 

2.  HORNBLENDE,  PYROXENE,  AND  CHRYSOLITE  ROCKS. 

In  these  rocks  chrysolite  when  present  is  often  changed 
to  serpentine,  and  sometimes  the  pyroxene  also. 

1.  Pyroxenyte. — Consists  of  augite,  coarse  or  fine  crystal- 
line-granular.    Sometimes  chrysolitic.     Cortlandt,  N.  Y., 
and  Stony  Point. 

2.  Picryts. — Blackish  green,  grayish  to  brownish   red. 
Crystalline-granular.     Consists  of   chrysolite,  with  augite 
or  diallage  or  hypersthene;  the  augite  sometimes  in  crystals; 
often  partly  altered  to  serpentine ;   also  some  magnetite. 
Graduates  into  chrysolitic  basalt.     Changes  to  hornblende- 
picryte,  and  into  a  serpentine  rock.     From  the  Fichtelge- 
birge.     Eulysyte  contains  also  garnet;  Sweden. 

Limburgyte  has  the  same  constituents,  but  is  glassy.  Silica  43  p.  c. 
From  Limburg  in  the  Kaiserstuhl. 

3.  Lherzolyte. — Greenish     gray  ;     crystalline-granular. 
Consists  of   chrysolite,    enstatite,   whitish   pyroxene  with 
chrome-spinel    (picotite)   and   sometimes   garnet.      Partly 
altered  serpentine.     From  Lake  Lherz. 

4.  Amphibolyte.     Hornblendyte. — Coarse  to  fine  crystal- 
line-granular. .  Either  massive  or  schistose.     Some  kinds 
chrysolitic.    Occurs  as  a  metamorphic  rock  as  well  as  erup- 
tive.    Sometimes  derived  from  the  alteration  of  an  augitic 
rock.     A  paler  green  variety,  consisting  of  actinolite,  has 
been  called  actinolyte. 

VARIETIES. — a.  Massive,  coarse  crystalline,  b.  Fine  crystalline. 
c.  Aphanitic.  d.  Chrysoliti*.  e.  Actinolyte^;  consisting  of  pale  green 
hornblende,  f.  Schistose;  Hornblende  schist. 


DESCRIPTIONS   OF   ROCKS.  489 

Common  as  a  schist  and  massive  rock  in  metamorphic  regions.  A 
coarsely  crystalline,  chrysolitic  eruptive  rock  at  Stony  Point,  on  the 
Hudson  River,  and  on  the  opposite  side  of  the  river  in  Cortlandt,  N.  Y. 

5.  Hornblende-Picryte. — Dark  greenish  to  greenish  black 
and  gray;  coarse  to  fine  grained.     Consists  of  hornblende, 
chrysolite,  and  serpentine,  with  magnetite;  the  hornblende 
mostly  or  wholly  altered  augite  and  the  serpentine  altered 
chrysolite;   usually  more  or  less  augite.     From  Anglesey 
and  Carnarvonshire. 

6.  Dunyte.      Peridotyte. — Pale    green,     grayish    green, 
granular ;    consisting  almost  wholly  of   chrysolite ;   often 
partly  changed  to  serpentine.     G.  =  3-3*1. 

From  Mt.  Dan  in  New  Zealand,  where  it  is  eruptive.  Also  from 
Macon  Co.,  N.  Carolina.  A  related  rock  is  supposed  to  be  the  origin 
of  the  serpentine  rocks  of  Baste  in  the  Hartz,  etc. 

7.  Glaucophanyte. — Consists  chiefly  of  the  blue  soda- 
bearing  hornblende,  glaucophane,  with  some  black  mica. 

From  Saxony;  Isle  of  Syra;  New  Caledonia;  Coast  region,  Cali- 
fornia (Becker).  An  epidotic  variety  is  reported  from  the  Alps. 

E.  HYDROUS  MAGNESIAN  AND  ALUMINOUS  ROCKS. 

1.  Chlorite  Schist. — Schistose;  color  dark  green  to  grayish 
green  and  greenish  black;  but  little,  if  any,  greasy  to  the 
touch.     Consists  of  chlorite,  with  usually  some  quartz  and 
feldspar  intimately  blended,  and  often   contains   crystals 
(usually  octahedrons)  of  magnetite,  and  sometimes  chlorite 
in  distinct  scales  or  concretions.     Metamorphic. 

VARIETIES. — a.  Ordinary,  b.  Hornblendic;  the  hornblende  in 
grains  or  needles,  c.  Magnetitic.  d.  Tourmalinic.  e.  Garnetiferous. 
f.  Pyroxenic.  g.  Staurolitic.  h.  Epidotic.  Graduates  into  argillyte. 

2.  Chlorite-Argillyte. — An  argillyte  or  phyllyte  consisting 
largely  of  chlorite.     Metamorphic. 

3.  Talcose  Schist. — A  slate  or  schist  consisting  chiefly  of 
talc.     Not  common,  except  in  local  beds,  most  of  the  so- 
called  "  talcose  slate"  being  hydromica  schist.     Listivicmyte 
is  a  variety,  from  the  Urals,  consisting  of  talc  and  granular 
quartz. 

4.  Steatyte,  Soapstone  (p.  326). — Consists  of  talc.     Mas- 
sive, more  or  less  schistose;  granular  to  aphanitic.     Color, 
gray  to  grayish  green  and  white.    Feels  very  soapy.    Easily 
cut  with  a  knife.     Metamorphic. 


490  DESCRIPTIONS  OF   ROCKS. 

VARIETIES. — a.  Coarse-granular,  and  massive  or  somewhat  scnis- 
tose.  b.  Fine-granular;  "French  chalk."  c.  Aphanitic,  or  JRens- 
selaerite ;  of  grayish-white,  greenish,  brownish  to  black  colors,  from 
St.  Lawrence  County,  N.  Y.,  and  Grenville,  Canada. 

5.  Serpentine. — Aphanitic  or  hardly  granular.     Easily 
scratched  with  a  knife.     Dark  green  to  greenish  black  in 
color,  and  often  a  little  greasy  to  the  feel  on  a  smooth  sur- 
face, but  sometimes  white,  pale  grayish,  yellowish  green, 
and  mottled.     Metamorphic. 

VARIETIES. — a.  Noble;  oil-green  and  translucent,  b.  Common; 
opaque,  and  of  various  colors,  c.  Schistose,  d.  Diallagic ;  contains 
green  or  metalloidal  diallage.  e.  Chromiferous ;  contains  chromite, 
a  chromium  ore  belonging  to  serpentine  regions,  f .  Bastitic  ;  contains 
bastite  or  enstatite.  g.  Grarnetiferous  ;  contains  garnet,  as  at  Zoblitz. 
h.  Chrysolitic  ;  contains  chrysolite,  i.  Brecciated;  consists  of  united 
fragments.  (See  also  page  330.)  Serpentine  often  has  a  crystalline- 
granular  texture,  and  sometimes  a  foliated,  which  it  owes  to  the 
mineral  from  which  it  was  made,  as  chlorite,  enstatite  hypersthene, 
pyroxene,  hornblende ;  which  minerals  often  occur  in  it  in  a  half- 
altered  state. 

6.  Ophiolyte.     (Verd- Antique    MarUe,    Ophicalce.) — A 
mixture  of  serpentine  with  limestone,  dolomite,  or  magnes- 
ite,  having  a  mottled  green  color.    Often  contains  dissemin- 
ated magnetite  or  chromite.     Metamorphic. 

VARIETIES.— a.  Calcareous;  the  associated  carbonate  being  calcite. 
b,  Dolymitic  ;  the  associated  carbonate,  dolomite,  c.  Magnesitic  ;  the 
associated  carbonate,  magnesite.  Either  of  these  kinds  may  contain 
chromite  or  magnetite.  Handsome  verd-antique  marble  has  been  ob- 
tained near  New  Haven  and  Milf ord,  Conn.  A  beautiful  variety,  hav- 
ing pure  serpentine  disseminated  in  grains  or  spots  through  a  whitish 
calcite,  occurs  at  Port  Henry,  Essex  County,  N.  Y.,  and  is  worked. 

7.  Pyrophyllyte  and  Pyrophyllite  Slate. — Like  the  pre- 
ceding in  appearance  and  soapy  feel,  but  having  the  com- 
position of  pyrophyllite  (p.  328).     The  color  is  white  and 
gray  or  greenish  white.     Occurs  in  North  Carolina.     One 
of  the  varieties  from  the  Deep  River  region  is  used  for  slate- 
pencils.     Metamorphic. 

The  iron  ores,  hematite,  magnetite,  limonite,  siderite,  have  rightly 
a  place  among  rocks,  as  they  constitute  beds  in  the  earth's  strata.  But 
they  have  already  been  sufficiently  described. 


DURABILITY   OF   ROCKS.  491 


VI.  DURABILITY  OF  ROCKS. 

1.  Sources  of  Weakness. — The  durability  of  a  rock  depends 
mainly  on  (ij  its  degree  of  porosity  or  soundness;  and  (2) 
the  presence  or  absence  of  a  mineral  of  easy  destruction  or 
easy  removal. 

The  porosity  may  be  general  in  the  rocks,  or  differ  along 
different  planes  or  laminae,  or  be  connected  in  part  with  the 
presence  of  a  fissile  mineral  like  mica,  or  be  increased  by 
rifts  or  cracks.  As  far  within  the  rock  as  water  and  air  can 
gain  access  together,  disintegration  or  decomposition  will 
be  going  on,  whatever  the  rock.  Water  by  itself  protects 
rocks — as  is  often  seen  on  rocky  seashores  where  the  rock 
below  half-tide  may  be  unchanged,  and  that  above  deeply 
decayed. 

The  weak  mineral  of  a  rock  may  be — 

A.  One  that  is  soluble,  and  hence  removable,  by  waters 
containing  either  carbonic  acid,  which  is  present  in  all 
waters,  or  organic  acids,  which  are  always  present  in  waters 
filtering  through  soils.     Calcite  is  one  such  mineral. 

B.  One  that  contains  a  removable  constituent,  such  as  an 
alkali  or  lime,  e.g.,  orthoclase,  which  loses  its  potash  through 
infiltrating  acid  (carbonic  or  organic)  waters,  and  thence 
changes  to  clay  or  kaolin. 

C.  One  that  contains  iron  in  the  protoxide  state,  such 
iron  tending  to  oxidize  further  and  pass  to  the  sesquioxide 
state,  producing  limonite  of  iron-rust  color,  or  (less  fre- 
quently) hematite  of  a  red  color;  e.g.,  black  mica,  pyroxene, 
hornblende. 

D.  One  that  contains  iron  combined  with  sulphur,  which 
iron  tends  to  pass  to  the  sesquioxide  state,  as  under  C;  but 
as  the  sulphur  also  oxidizes  into  sulphuric  acid,  iron  sulphate 
may  result;  e.g.,  pyrite,  pyrrhotite,  marcasite. 

Porosity  and  the  presence  of  rifts  or  cracks  give  an  op- 
portunity for  these  methods  of  destruction  by  solution  and 
oxidation  to  act.  In  an  exposed  ledge,  the  depth  to  which 
oxidation,  or  loss  of  firmness,  extends  is  an  indication  of 
the  depth  of  porosity.  In  some  granites  the  depth  (or  the 
thickness  of  the  sap,  as  the  quarryman  sometimes  calls  it) 
is  a  yard  or  more;  in  the  best,  a  line  or  less. 


492  DURABILITY   OF   ROCKS. 

The  methods  of  decay  are  then  as  follows: 

a.  By  method  A:  as  when  a  crystalline  limestone,  if  it  is 
a  dolomite  containing  some  calcite  (p.  460),  loses  its  calcite 
through  infiltrating  waters  and  crumbles  to  sand — a  common 
fact  in  Westchester  Co.,  N.  Y.,  Berkshire  Co.,  Mass.,  and 
many  other  regions. 

b.  By  method  B:  as  when  a  granite  has  its  feldspar  weak- 
ened or  turned  to  kaolin,  and  becomes  weak  or  crumbling. 

c.  By  method  C:  as  when  granite  has  its  black  mica 
rusted  and  destroyed,  causing  the  rock  to  become  a  granite 
sand  consisting  of  feldspar  and  quartz — a  common  occur- 
rence; or  when  trap,  a  rock  consisting  of  a  feldspar  (labra- 
dorite)  and  pyroxene,  becomes  changed  more  or  less  deeply 
to  rusty  rock  or  rusty  earth;  the  depth  hardly  a  line  in  the 
most  anhydrous  and  durable,  but  many  yards  in  the  poorer 
hydrous  kinds. 

d.  By  method  D :  as  when  any  rock,  of  the  legion  con- 
taining pyrite,  has  the  pyrite  rusted  (oxidized)  and  changed 
to  limonite  or  hematite,  or  to  sulphate,  to  the  discoloration 
and  decay  of  the  rock — a  very  common  evil  in  carelessly  se- 
lected building-stones. 

Besides  these  there  are  also  several  mechanical  sources  of 
destruction  attending  methods  B,  C,  D,  owing  their  effi- 
ciency to  the  fact  that  the  introduction  of  material  among 
grains  or  into  rifts,  by  chemical  change  or  otherwise,  is  an 
introducing  of  wedges,  pushing  the  grains  apart,  and  open- 
ing and  extending  rifts. 

These  are  the  following: 

e.  In  method  B,  the  feldspar  loses  silica  as  well  as  al- 
kali,— at  least  one  third  of  its  66  p.  c., — and  this  may  de- 
posit about  the  grains,  or  in  the  rifts  of  the  rock  deepening 
and  multiplying  them,  and  be  so  infinitesimal  in  amount 
that  it  is  only  with  difficulty  detected. 

/.  In  method  C,  oxygen  is  introduced,  and  the  resulting 
oxide  with  the  rest  of  the  mineral  takes  more  space  than 
the  unaltered  mineral;  and  here  again  there  is  a  wedging  or 
divellent  action. 

g.  In  method  D,  besides  the  same  action  as  under  f,  the 
sulphuric  acid  formed  may  combine  with  alkalies,  lime,  iron, 
alumina,  present  in  the  rock,  and  make  other  wedges,  be- 
sides adding  directly  in  a  chemical  way  to  the  destructive 
action. 

In  addition,  there  are  other  mechanical  methods  of  de- 


DURABILITY   OF   ROCKS.  493 

cay  which  work  either  molecularly  or  in  the  large  way. 
These  are: 

//.  Alternate  heating  and  cooling,  from  changes  in  tem- 
perature between  exposures  to  sunshine  and  shadow,  day  and 
night,  warm  seasons  and  cold,  sun's  heat  on  rocks  during 
the  day  and  the  cold  waters  of  the  returning  tide,  and  so 
on,  causing  expansion  and  contraction,  and  thence  superfi- 
cial disintegration  of  granule  after  granule;  or  the  separa- 
tion of  scales  or  plates  parallel  to  the  surface;  or  producing 
a  laminated  or  jointed  structure  on  a  large  scale,  as  in  some 
granitoid  rocks  (e.g.,  the  concentric  structure  of  the  Yose- 
mite  granite  peaks).  The  unequal  expansion  caused  by  a 
given  amount  of  heat  in  the  different  minerals  of  a  granite 
is  supposed  to  enhance  the  disintegrating  effect. 

i.  The  freezing  of  water;  expansion  taking  place  on 
freezing  (p.  251),  exerting  a  tearing  action,  both  among 
surface  grains  and  in  rifts  or  fissures,  and  covering  the 
slopes  beneath  rocky  bluffs  in  cold  climates  with  debris. 

j.  The  growth  of  microscopic  life  (as  microbes  and  mi- 
nute algae  or  fungi)  in  rifts  and  pores  introduces  growing 
wedges,  having  a  tearing  action,  extending  rifts,  etc. 

The  growth  of  roots  and  stems  of  larger  plants  wedges 
open  rifts  and  joints  on  a  large  scale,  sometimes  moving 
blocks  weighing  hundreds  of  tons. 

k.  Further,  organic  material,  living  and  dead,  is  the  oc- 
casion of  destruction  by  chemical  means.  The  living  may 
give  out  oxygen  and  carbonic  acid;  and  the  dead  may  pro- 
duce by  their  decay  organic  acids,  carbonic  oxide,  and  car- 
bonic acid.  Moreover,  the  living  microbes  may,  according 
to  their  kinds,  promote  oxidation  and  deoxidation,  nitrifica- 
tion and  denitrification,  and  so  be  the  initiator  of  change  and 
destruction,  as  they  are  of  fermentation  and  decay,  and  a 
medium  of  right  functional  action  in  the  processes  of  life. 

Eocks  have  often  retained  the  glacier  markings  upon 
them  perfectly  fresh  until  now,  when  they  have  had  a  cov- 
ering of  two  or  three  feet  of  earth;  and  they  have  lost  such 
markings  after  a  few  years  of  exposure.  This  happens  often 
without  true  decomposition  or  oxidation.  The  preservation 
of  the  scratches  may  be  due  partly  to  the  water  of  the  soil, 
but  also  in  part,  and  perhaps  most  largely,  to  freedom  from 
the  expansion  and  contraction  which  is  caused  by  changing 
temperature. 

In  granite  and  sandstone,  the  less  mica  the  more  durable 


494  DURABILITY   OF   BOCKS. 

the  rock,  because  mica  tends  to  increase  porosity.  In  all 
firm  rocks,  closeness  of  texture  or  fineness  of  grain  is  fa- 
vorable to  durability.  There  is  no  more  durable  rock  than 
a  good  roofing  slate.  Good  granites,  when  well  polished, 
will  usually  resist  all  weathering  agencies;  because  the  pol- 
ished surface  has  no  depressions  to  catch  and  hold  water, 
but  dries  almost  immediately  after  wetting. 

To  ascertain  the  durability  of  a  rock,  the  first  step  is  to 
examine  the  rock  in  its  native  ledges ;  if  durable  there, 
it  will  be  durable  in  man's  structures,  and  not  otherwise. 
The  practice  of  testing  the  durability  of  a  stone  for  archi- 
tectural purposes  by  putting  it  into  water,  and  then  weigh- 
ing it,  after  some  days  of  exposure,  to  see  whether  it  has 
gained  in  weight,  is  a  good  one.  Durability  depends  much 
on  the  climate.  In  Peru  even  sunburnt  bricks  will  last 
for  centuries. 

2.  Resistance  to  Crushing. — The  resistance  to  crushing 
in  rocks  is  ascertained  by  subjecting  cubes  of  a  given  size 
to  pressure;  for  the  best  results  the  pressure  should  be  very 
slowly  applied.  In  recent  experiments  by  P.  Michelot,* 
Minister  of  Public  Works  in  France  (whose  trials  num- 
bered over  10,000),  the  most  compact  limestones,  weighing 
2700  kilograms  per  cubic  metre,  were  crushed  by  a  weight 
of  900  kilograms  per  square  centimetre.  Compact  oolitic 
limestone  of  Bourgogne  and  some  other  French  localities, 
weighing  2600  to  2700  kilograms,  bore  700  to  900  kilograms 
before  crushing.  Statuary  and  decorative  marbles  bore  500 
to  700  kilograms. 

Of  granitic  rocks  from  Brittany,  the  Cotentin,  the  Vosges, 
and  the  Central  Plateau  of  France,  weighing  2600  to  2800 
kilograms,  the  best,  which  admitted  of  polishing,  bore  1000 
to  1500  kilograms;  while  the  coarser  granites  of  Brest  and 
Cherbourg  and  the  syenyte  of  the  Vosges  bore  700  to  1000 
kilograms;  and  other  coarse  granites,  in  which  the  large 
crystals  of  feldspar  were  in  part  decomposed,  bore  only  400 
to  600  kilograms.  The  green  porphyry  of  Ternuay  (Haute 
Saone),  bore  1360  kilograms;  the  basalt  of  Estelle  (Puy  de 
Dome),  1880  kilograms. 

In  trials  by  Gen.  Gilmore,  trap  of  New  Jersey  required 
to  crush  it  20,750  to  24,040  pounds  a  square  inch  ;  granite 

*  Exposition  Universelle  de  1873  a  Vienne,  pp.  401-432;  and  Annales  des  Fonts 
et  Chauss6es,  1863, 1868, 1870. 


DURABILITY   OF   ROCKS.  495 

of  Westerly,  R.  I.,  17,750;  id.  of  Richmond,  Va.,  21,250 
syenyte  of  Quincy,  17,750;  marble  of  Tuckahoe,  N.  Y. 
12,950;  id.  of  Dorset,  Vt.,  7612;  limestone  of  Joliet,  111. 
11,250;  sandstone  of  Belleville,  N.  J.,  10,250;  id.  of  Port 
land,  Ct.,  6950;  id.  of  Berea,  0.,  8300;  id.  of  Amherst,  0. 
6650;  id.  of  Medina,  N.  Y.,  17,250;  id.  of  Dorchester,  N.  B. 
9150. 

Trials  of  ArcJman  granites  in  Minnesota,  by  Mr.  J.  Co- 
croft  gave  26,200  pounds  per  square  inch  for  the  mean  of 
20  samples,  and  23,318  pounds  when  crushed  between 
wooden  cushions. 

When  absorbent  rocks  are  thoroughly  wet  the  weight  re- 
quired to  crush  them  is  greatly  reduced.  Crushing  of  wet 
chalk,  according  to  trials  by  Delesse,  required  only  one 
third  what  the  stove-dried  required;  and  for  the  limestone, 
"calcaire  grossier,"  of  Vitry  and  other  localities,  mostly 
one  third  to  one  half.  Tournaire  and  Michelot  found,  for 
the  chalk  of  the  Paris  basin,  the  pressure  required  when  wet 
two  ninths  of  that  required  when  the  rock  had  been  dried 
at  a  temperature  considerably  above  212°  F. 


ACADEMY  MINERAL  COLLECTION. 

FOR  the  convenience  of  instructors  in  Academies  or 
High  Schools,  a  catalogue  is  here  inserted  of  the  more 
desirable  species.  The  collection,  made  up  according  to 
it,  would  include  125  specimens.  The  cost  will  depend  on 
the  size  and  quality  of  the  specimens  :  with  specimens  aver- 
aging in  size  2x2^  inches,  it  need  not  exceed  twenty  dol- 
lars ;  and  if  made  forty  dollars,  it  should  obtain  an  excellent 
collection,  the  specimens  averaging  3x3  inches,  and  many 
of  them  crystallized.  The  number  following  the  name  of 
each  mineral  is  that  of  the  page  where  described. 

1.  Sulphur,  106.  12.  Malachite,  154. 

13.  Galenite,  160. 

14.  Pyromorphite,  167. 

15.  Cerussite,  168. 

16-18.  Sphalerite:  black,  yellow, 
etc.,  170. 

19.  Zincite,  171. 

20.  Willemite,  173. 

21.  Calamine,  174. 

22.  Cassiterite,  176. 

23.  Rutile,  179. 


2.  Stibnite,  112. 

3.  Graphite,  119. 

4.  Gold  in  quartz,  122. 

5.  Silver,  129. 

6.  An  ore  of  Silver. 

7.  Cinnabar,  143. 

8.  Copper,  145. 

9.  Chalcopyrite,  147. 

10.  Tetrahedrite,  150. 

11.  Cuprite,  151. 


496 


ACADEMY  MINERAL  COLLECTIOK. 


24.  Garnierite,  185. 
25-27.  Pyrite:  crystals,  massive, 
189. 

28.  Pyrrhotite,  192. 

29.  Arsenopyrite,  192. 

30-32.  Hematite:  crystallized, 
massive,  red  ochre,  193. 

33.  Magnetite:   crystals,  massive, 

196. 

34.  Franklinite,  197. 

35.  Cliromite,  197. 

36-38.  Limonite:  stalactitic  or 
botryoidal,  yellow  ochre, 
bog  ore,  198. 

39.  Columbite,  201. 

40.  Siderite,  203. 

41.  Pyrolusite,    or   other   Man- 

ganese oxide,  206,  207. 

42.  Corundum,  211. 

43.  Spinel,  213. 

44.  Cryolite,  216. 

45.  An  Alum,  217. 

46.  Magnesite,  226. 

47.  Fluorite,  227. 

48-50.  Gypsum:  crystal,  selenite, 

massive,  229. 
51.  Anhydrite,  230. 
54.  Apatite,  232. 
55-60.  Calcite:    cryst.,   cleavage, 

rhombohedron,  stalagmite, 

ma?^a»,  common  limestone, 

chalk,  235. 

61.  Aragonite,  237. 

62,  63.     Dolomite:    Pearl    Spar, 

Marble,  238. 

64.  Barite,  240. 

65.  Celestite,  242. 

66.  Halite,  243. 

67-74.  Quartz:  cryst.,  milky, 
smoky,  chalcedony,  agate, 
hornstone  (or  flint  or  chert), 
jasper,  253. 

75,  76.  Opal:  common,  tripolite, 
259. 


77,  78.  Pyroxene':  cryst.,  massive 
cleavable,  265. 

79.  Khodonite,  268. 

80.  Spodumene,  269. 

81-84.  Hornblende:  black,  green 
(actinolite),  white  (tremo- 
lite),  asbestus,  270. 

85.  Beryl,  274. 

86.  Chrysolite,  277. 

87-89.  Garnet:  crystals,  crystals 
in  the  rock,  278. 

90.  Zircon,  281. 

91.  Vesuvianite,  282. 

92.  Epidote,  283. 

93.  Zoisite,  285. 

94.  95.  Muscovite,  288. 

96.  Biotite,  291. 

97.  Scapolite,  292. 

98.  Albite,  299. 

99.  100.  Orthoclase:  cryst ,  cleav- 

able piece,  300. 
101,  102.  Tourmaline,  304. 

103.  Andalusite,  306. 

104.  Cyanite,  308. 

105.  Topaz,  309. 

106.  Sphene,  312. 

107.  108.  Staurolite:  cryst.,  one 

cruciform,  313. 

109.  Apophyllite,  316. 

110.  Prehnite,  317. 

111.  Natrolite,  321. 

112.  Chabazite,  322. 

113.  Stilbite,  324. 

114-116.  Talc:  foliated,  massive 
(soapstone),  French  chalk, 
or  rensselaerite,  326. 

117.  Glauconite,  329. 

118,  119.  Serpentine,  329. 

120.  Kaolinite,  332. 

121.  Chlorite,  339  or  340. 

122.  Asphaltum,  349. 

123.  Anthracite,  350. 

124.  Bituminous  Coal,  351. 

125.  Cannel  Coal,  351. 


GENERAL   INDEX. 


Where  there  are  two  or  more  entries  after  a  name,  the  first  (if  the  name  is 
that  of  a  mineral  species)  is  the  page  on  which  the  species  is  described,  and  a 
semicolon  separates  it  from  the  following  entries. 


Aca'dialite,  323. 
Acan'thite,  131. 
Achre'matite,  168. 
Ac'mite,  268. 
Actin'olite,  271. 
Actin'olyte,  488. 
Adamantine  spar,  212. 
Adamite,  172. 
Adula'ria,  Adular,  301. 
JEgirine,  ^Egyrite,  268. 
JErinite,  337. 
^Eschynite,  222. 
Agalmat'olite,  326,  335,  474 
Ag'ate,  256. 

Agric'olite  =  Eulytine,  278. 
Aikinite,  164. 
Ajkite,  349. 
Alaban'dite,  206. 
Alabas'ter,  229. 
Alas'kaite,  164,  165. 
Al'bertite,  349. 
Albite,  299;  45,  59. 
Alexandrite,  215. 
Algod'onite,  149. 
Alipite,  185. 
Allak'tite,  210. 
Allanite,  284. 
Allemontite,  113. 
Allopalladite,  142. 
Allophane,  318. 
Allophite,  339. 
Alluaudite,  209. 
Alluvium,  465. 
Almandin,  Almandite,  279. 
Alshedite,  313. 
Altaite,  164. 
Alum,  native,  217. 
Alum  shale,  463. 
Alum  stone,  217. 
Alu'minite,  218. 

Aluminium,  Compounds  of,  211. 
fluorides,  216. 


Al'unite,  217. 
Alu'nogen,  216. 
Alvite,  282. 
Amalgam,  130. 
Amazoustone,  300. 
Amber,  348. 
Amblyg'onite,  218;  44. 
Amblystcgite,  264;  456. 
Am'brite,  349. 
Amesite,  341. 
Amethyst,  255. 

Oriental,  212. 
Am'ian'thus,  271,  330. 
Ammo'nium  alum,  217. 
Ammonium,  Salts  of,  249. 
Am'phibole,  270. 
Amphib'olyte,  488. 
Am'phigene,  295. 
Amphig'enyte,  479. 
Amyg'daloid,  485. 
Anal 'cite,  Analcime,  322. 
Anam'esyte,  485. 
An'atase,  180. 
An'cramite,  175. 
Andalu'site,  306,  452,  456. 
An'desiue,  Andesite,  299. 
An'desyte,  483. 
An'dradite,  279. 
An'drewsite,  203. 
An'glesite,  165. 
Anhy'drite,  230. 
Animikite,  132. 
Ankerite,  239;  204. 
Annabergite,  184. 
Annerodite,  221. 
Annite,  291. 
Ano'mite,  291. 
Anor'thite,  298;  457. 
Anorthite  rocks,  486. 
Anorthityte,  486. 
Anthophyl'lite,  273. 
An'thracite,  351. 


498 


GEKEKAL  IKDEX. 


Anthrac'onite,  237. 
Antig'orite,  330. 
Antillite,  331. 
Antimonate,  Calcium,  234. 

Copper,  154. 

Lead,  168. 
Antimonial  copper  ores,  149, 150. 

lead  ores,  167,  168. 

nickel  ores,  183. 

silver  ores,  132. 
Antiino'nite  =  Stibnite,  112. 
Antimony,  Gray,  112. 

Native,  112. 

Red,  113. 

glance  =  Stibnite. 
Antrim'olite,  321. 
Ap'atite,  232;  47,  50,  455. 
Aphane'site,  153. 
Aph'rodite,  328. 
Aphrosiderite,  341. 
Aphthit'alite,  246. 
Apjohnite,  217. 
Aplome,  279. 
Ap'lyte,  471. 
Apoph'yllite,  316. 
Aquamarine,  274. 
Arag'onite,  237;  452. 
Arago'tite,  348. 
Arcanite,  246. 
Arctolite,  285. 
Arden'nite,  285. 
Arequi'pite,  168. 
Arfved'sonite,  273. 
Argentane,  186. 
Argen'tine,  236. 
Argen'tite,  131. 
Argentopyrite,  131. 
Ar'gillyte,  463,  473. 
Argyropyrite,  131. 
Ante,  183. 
Arkansite,  180. 
Arkose,  462. 
Arksutite,  216. 
Arnimite,  153. 
Ar'querite,  130. 
Arrag'onite,  «.  Aragonite. 
Arsenate,  Calcium,  234. 

Cobalt,  184. 

Copper,  153. 

Iron,  203. 

Lead,  167. 

Uranium,  188. 

Zinc,  172. 


Arsenic,  Native,  110. 

White,  111. 
Arsenic  group,  110. 

sulphide,  111. 
Arsenical  antimony,  113. 

cobalt,  182. 

iron  ore,  192,  193. 

lead  ores,  164. 

nickel,  182. 
Arseniosid'erite,  203. 
Arsen'olite,  111. 
Ar'senopy'rite,  192. 
Asbestus,  266,  271,  330. 

Blue  or  Crocidolite,  273. 
Asbolan,  Asbolite,  183,  208. 
Asmanite,  262. 
Asparagus  stone,  233. 
Aspa'siolite,  336. 
Asphal'tum,  349. 
Aspid'olite,  290. 
Astrak'anite  v.  Blodite. 
Astrohpyllite,  292. 
Ataca'mite,  150. 
Atelestite,  114. 
Atelite,  151. 
Atopite,  234. 
Auerbachite,  282. 
Augite,  265;  442,  451. 
Augite-andesyte,  483. 
Augite-dioryte,  482;  483. 
Augite-granite,  478. 
Augite-syenyte,  478. 
Augitic  trachyte,  475. 
Aurichalcite,  156, 173. 
Auriferous  pyrite,  190. 
Auripigmentum,  111. 
Aurum  musivum,  178. 
Autom'olite,  214. 
Autunite,  188. 
Av'alite,  185. 
Aventurine  quartz,  255. 

feldspar,  301. 
Ax'inite,  286. 
Az'urite,  156. 

Bab'ingtonite,  268. 
Bagrationite  ®.  Allanite. 
Baltimorite,  330. 
Balvraidite,  285. 
Ban'atite,  481. 
Bar'cenite,  144. 
Barite,  38,  240. 
Barium,  Compounds  of,  240. 


GENERAL  INDEX. 


499 


Bar'sowite,  298. 
Bar'ylite,  286. 
Bar'ytes,  240. 
Barytocalcite,  242. 
Baryturanite,  188. 
Basalt,  485. 
Ba'sanite,  257. 
Bastite,  331. 
Bastnasite,  223. 
Bathvillite,  349. 
Beaumontite,  326. 
Beauxite,  213. 
Beccarite,  281. 
Bechilite,  232. 
Begeerite,  164. 
Belvraidite,  285. 
Benzole,  324. 
Bcrgamaskite,  272. 
Berthierite,  193. 
Bertrandite,  275. 
Beryl,  274. 
Berzelianite,  149. 
Berzeliite,  234. 
Bcyrichite,  181. 
Bieberite,  185. 
Biharite,  335. 
Bindheimite,  168. 
Binnite,  149. 
Biotite,  291. 
Bischofite,  224. 
Bismite,  114. 
Bismuth,  113. 
Bismuthinite,  114. 
Bismuth  ores,  113,  114,  150. 

carbonate,  114. 

nickel,  183. 

silver,  129. 

telluride,  114. 
Bismutite,  114. 
Bismutoferrite,  278. 
Bismutospha3rite,  114. 
Bitter  spar,  v.  Dolomite. 
Bitumen,  349. 

Elastic,  347. 
Bituminous  coal,  350. 
Bituminous  shale,  463. 
Bjelkite,  164. 
Black  cobalt,  183. 

copper,  151. 

jack,  170. 

lead,  120. 

silver,  133. 
Blende,  170. 


Blodite,  225. 
Blomstrandite,  187. 
Bloodstone,  257. 
Blue  iron  earth,  202. 

copper,  147. 

vitriol,  152. 
Bo'denite,  284. 
Bog  iron  ore,  198. 

manganese,  207. 
Bole,  335. 
Bolivite,  114. 
Boltonite,  277. 
Boracic  acid,  109. 
Boracite,  225. 
Borate,  Aluminium,  218. 

Ammonium,  250. 

Calcium,  231. 

Hydrogen,  109. 

Iron,  200. 

Magnesium,  225. 

Sodium,  231. 
Bo'rax,  246. 
Bordosite,  130. 
Bor'nite,  148. 
Bo'rocal'cite,  231. 
Boronatrocalcite,  231. 
Boron  group,  109. 
Bort,  116. 
Bosjemanite,  217. 
Bot'ryogen,  200. 
Bot'ryolite,  311. 
Boulan'gerite,  164. 
Bour'nonite,  149. 
Boussingaultite,  250. 
Bowenite,  331. 
Brackebuschite,  168. 
Bragite,  282. 
Branchite,  348. 
Bran'disite,  342. 
Brass,  composition  of,  159. 
Braunite,  207. 
Bravaisite,  329. 
Breccia,  462. 
Bredbergite,  279. 
Breislakite,  271. 
Breithauptite,  183. 
Breunnerite,  226. 
Brewsterite,  326. 
Brittle  silver  ore,  133. 
Brochantite,  153. 
Br5ggerite,  187. 

Bromic  silver,  Bromargyrite,  134. 
Bromlite,  242. 


500 


GENERAL  INDEX. 


Bromyrite  (Bromic  silver),  134 
Brongniardite,  133;  164. 
Bronze,  159. 
Bronzite,  264. 
Brookite,  180. 
Brown  coal,  351. 

hematite,  198. 

iron  ore,  198. 

ochre,  181,  198w 

spar,  239. 

stone,  462. 
Brucite,  223. 
Brashite,  234. 
Buchol'zite,  307. 
Buchonitfi.  486.  * 
Bucklandite,  284. 
Buhrstone,  469. 
Bunsenine=:Krennerite,  129. 
Bu'ratite.  173. 
Bytownite,  298. 

Cabrerite,  184. 
Cach'olong,  260. 
Cacox'enite,  Cacoxene,  203. 
Cadmium,  Ores  of,  175. 
Cairngorm  stone,  255. 
Caking  coal,  351. 
Cal'aite,  v.  Callaite. 
Cal'amine,  174. 
Cal'ave'rite,  129. 
Calcite,  234;  51,  453,  455. 
Calcium,  Compounds  of,  227. 
Calc  spar,  234. 
Calcd'onite,  186. 
Callai'nite.  219. 
Callais,  Callaite,  219. 
Calomel,  143. 
Ca'naanite,  461. 
Cancrinite,  294. 
Cannel  coal,  351. 
Cautonite^Covellite,  147. 
Caoutchouc,  Mineral,  347. 
Capillary  pyrites,  181. 
Cappelenite,  275,  306. 
Carbonaceous  shale,  463. 
Carbonado,  116. 
Carbonate,  Calcium,  234. 
Carbonate,  Bismuth,  114. 

Copper,  154,  156. 

Iron,  203. 

Lead,  168. 

Magnesium,  226. 

Manganese,  210. 


Carbonate,  Sodium,  249. 
Strontium,  242. 
Uranium,  187. 
Yttrium,  223. 
Zinc,  172. 

Carbonic  acid,  120;  448. 

Carburetted  hydrogen,  342. 

Carnal'lite,  224. 

Carne'lian,  256. 

Car'pholite,  318. 

Carra'ra  marble,  433. 

Carrollite,  181. 

Caryinite,  234. 

Cassinite,  302. 

Cassit'erite,  176. 

Castor,  Castorite,  270. 

Catapleiite,  317. 

Cataspi  lite,  335. 

Cat'linite,  464. 

Cat's-eye,  256. 

Celad'onite,  329. 

Celestialite,  349. 

Celes'tite,  Celestine,  242. 

Cement  stone,  236. 

Cerar'gyrite,  134. 

Cerite,  318. 

Cerium  ores,  221. 

Ce'rolite,  332. 

Cerus'site,  168. 

Cervan'tite,  113. 

Chab'azite,  322. 

Chalcan'thite,  152. 

Chalccd'ony,  255. 

Chal'cocite,  146. 

Chal'codite,  329. 

Chalcolite,  187. 

Chal'come'nite,  154. 

Chalcomorphite,  319. 

Chalcoph'anite,  208. 

Chalcophyl'lite,  154. 

Chalcopy'rite,  147. 

Chalcosid'erite,  203. 

Chalcosine  =  Chalcocite,  146. 

Chalcosti'bite,  149. 

Chalcotri'chite  =  Capillary     Cu- 
prite. 

Chalk,  236. 

Chal'ybite,  203. 

Chamasite,  189. 

Chathamite  v.  Chloanthite. 

Chen'evixite,  154. 

Chert,  256,  469. 

Chelmsfordite,  293. 


GENERAL   INDEX. 


501 


Chesterlite,  300. 
Chias'tolite,  307. 
Childrenite,  219. 
Chiolite,  216. 
Chiviatite,  149,  150. 
Chloanthite,  181. 
Chloraluminite,  216. 
Chlorastrolite,  317. 
Chloride,  Ammonium,  249. 

Copper,  150. 

Lead,  165. 

Magnesium,  224. 

Mercury,  143. 

Potassium,  243. 

Silver,  134. 

Sodium,  243. 
Chlorite,    Chlorite    Group,  337, 

449. 

Chlorite  schist,  489. 
Chlorite-argillyte,  489. 
Chloritoid,  341. 
Chlormagnesite,  224. 
Chlorocalcite,  229. 
Chloropal,  329. 
Chlorophaeite,  340. 
Chlo'rophane,  237. 
Chlo'rophyl'lite,  336. 
Chlorospinel,  214. 
Chlorothionite,  153. 
Chlorotile,  154. 
Chodneffite,  216. 
Chon'drodite,  303. 
Chon  icrite,  338. 
Chromate,  Lead,  166. 
Chrome  yellow,  166. 
Chromic  iron,  197. 
Chromite,  197.   ' 
Chromium  sulphide,  198. 
Chrysoberyl,  215. 
Chrysocolla,  157. 
Chrysolite,  277;  442,  449,  453, 456. 
Chrysolyte,  0.  Peridotyte. 
Chrysoprase,  255. 
Chrysotile,  330. 
Churchite,  222. 
Cimolite,  328. 
Cin'nabar,  143. 
Cinnamon  stone,  279. 
Cip'olin  marble,  461. 
Citrine,  255. 
Clarite,  149. 
Claudetite,  111. 
Clausthalite,  164. 


Clay,  464. 

iron-stone,  198,  204. 

slate,  463. 
Cleavelandite,  300. 
Cleiophane,  171. 
Cleveite,  187. 
Clingmanite,  341. 
Clinkstone,  479. 
Cli'nochlore,  340. 
Clinoclasite,  153. 
Clinochrocite,  200. 
Clinohumite,  304. 
Clinophalite,  200. 
Clintonite,  342. 
Coal,  Mineral,  350. 

Brown,  351. 

Cannel,  351. 
Cobalt,  Ores  of,  180. 
Cobalt  bloom,  184. 

glance,  181. 

pyrites,  181. 

vitriol,  185. 

Cobaltite,  Cobaltine,  182. 
Cobaltomenite,  184. 
Coccolite,  266. 
Coke,  352,  354. 
Colemanite,  231. 
Collyrite,  318. 
Coloph'onite,  279. 
Colora'doite,  143. 
Columbite,  201. 
Columbium,  202. 
Comptonite,  320. 
Confolensite,  329. 
Conglomerate,  461. 
Conichalcite,  154. 
Connellite,  49  (f.  11),  153. 
Cookeite,  335. 
Copal,  Mineral,  349. 
Copaline,  Copalite,  349. 
Copi'apite,  200. 
Copper,  Ores  of,  145. 
Copper,  Native,  145. 

Black,  151. 

froth,  154. 

glance,  146. 

Gray,  150. 

mica,  154. 

nickel,  182. 

pyrites,  147. 

Red,  151. 

silicate,  156,  157. 

vitriol,  152. 


502 


GENERAL  INDEX. 


Copperas,  199. 
,  Coprolites,  233. 
Coquim'bite,  200. 
Coracite,  187. 
Cor'dierite,  287. 
Corneous  lead,  169. 
Cornwallite,  154. 
Coronguite,  168. 
Corsyte,  486. 
Corun'dellite,  341. 
Corundoph'ilite,  341. 
Corundum,  211. 
Co'salite,  164. 
Cossaite,  290. 
Cotun  nite,  165. 
Covel'lite,  Covelline,  147. 
Crednerite,  207. 
Crocid'olite,  273. 
Cro'coite,  Crocoisite,  166. 
Cron'stedtite,  341. 
Crooke'site,  149. 
Cry'olite,  216. 
Cry'ophyl'lite,  290. 
Cryptohalite,  250. 
Cryptolite,  222. 
Cryp'tomor'phite,  231. 
Cu'banite,  148. 
Cube  ore,  203. 
Culsageeite,  339. 
Cummingtonite,  272. 
Cu'prite,  151. 
Cuproscheelite,  232. 
Cuprotungstite,  153. 
Cuspidite,  277. 
Cyanite,  308;  457. 
Cyanotrichite,  153. 
Cymat'olite,  269. 
Cyprine,  282. 

'Dacyte,  483. 
Daleminzite,  131. 
Dam'ourite,  290,  335. 
Damourite  schist,  473. 
Da'naite,  193. 
Danalite,  278. 
Danburite,  286. 
Darwinite=Whitneyite,  149. 
Datholite,  Datolite,  311. 
Daubreelite,  198. 
Daubreite,  114. 
Davreuxite,  308. 
Davyne,  294. 
Dawsonite,  220. 


Dechenite,  168. 
Degeroite,  338. 
Delanouite,  329. 
Delawarite,  302. 
Delessite,  340. 
Del  vauxite = Duf  renite. 
Dendrites,  63,  449. 
Derbyshire  spar,  228. 
Descloi'zite,  168. 
Desmine,  325. 
Destinegite,  203. 
Detritus,  465. 
Deweylite,  332. 
Diabantachronyn,  340. 
Diaban  tite,  340. 
Di'abase,  445,  485. 
Diaclasite,  264. 
Diadelphite,  210. 
Di'allage,  Green,  267. 
Dial'logite=Rhodochrosite,  210. 
Diamond,  115. 
Diaphorite,  134. 
Di'aspore,  213. 

Diatomite,  Diatom  earth,  261,466. 
Di'chroite,  287. 
Dickinsonite,  209. 
Didymium  ores,  222,  223. 
Dietrichite,  217. 
Dihy'drite,  154. 
Dinite,  348. 
Diopside,  266. 
Dioptase,  156;  278. 
Di'oryte,  481. 
Dioryte  schist,  481. 
Orbicular,  486. 
Diphanite,  341. 
Dipyre,  293. 
Dister'rite,  342. 
Disthene,  308. 
Ditroyte,  479. 
Dog-tooth  Spar,  235. 
Doleroph'anite,  152. 
Dol'eryte,  484;  442,  445. 
DoVomite,  238;  455. 
Dol'omyte,  458,  460. 
Domey'kite,  149. 
Do'myte,  475. 
Dopplerite,  349. 
Dree'lite,  241. 
Dudleyite,  341. 
Du'f renite,  203. 
Du'frenoy'site,  164. 
Dumortierite,  308. 


GENERAL  INDEX. 


503 


Dumreicherite,  217. 
Du'nyte,  489. 
Durangite,  219. 
Durfeldtlte,  164. 
Dutch  white,  241. 
Duxite,  349. 
Dysanalyte,  234;  222. 
Dys'crasite,  132. 
Dysluite,  215. 
Dysodile,  349. 
Dysyn'tribite,  335,  474. 

Ecdemite,  167. 
Eclogyte,  487. 
Edel  forsite,  265. 
E'denite,  273. 
Ed'ingtonite,  318. 
Edmonsonite,  189. 
Ed  wardsite — Monazite. 
Eggonite,  175. 
Ehlite,  154. 
Ekebergite,  293. 
Ekmannite,  338. 
Elae'olite,  293. 
Elat'erite,  347. 
Electro-silicon,  261,  466. 
Electrum,  123. 
Eliasite,  187. 
Elpasolite,  216. 
•Em  bolite,  134. 
Emerald,  274. 

Oriental,  212. 
Emerald-nickel,  185. 
Emery,  211. 
Emery  lite,  341. 
Emmonsite,  203. 
Emplectite,  149. 
Empholite,  308. 
Enar'gite,  149. 
Enceladite,  v.  Warwickite. 
Endlicjiite,  167. 
Enstatite,  264;  456. 
Eos'phorite,  220. 
Eozoon,  331. 
Epichlorite,  338. 
Epidosyte,  488. 
Epidioryte,  482. 
Ep'idote,  283;  457. 
Epistil'bite,  326. 
Epsom  salt,  Epsomite,  224. 
Erbium  ores,  222. 
Erdman'nite,  318. 
Er'inite,  153. 


Eriochalcite,  151. 
Erubescite,  148. 
Er'ytlmte,  184. 
Erythrosiderite,  193. 
Erythrozincite,  171. 
Esmarkite,  336. 
Essonite,  279. 
Ettringite,  231. 
Eucairite,  132;  149. 
Euchlorite,  291. 
Eu'chroite,  153. 
Euclase,  311. 
Eucolite,  275. 
Eucrasite,  318. 
Eucryptite,  294. 
Eucryte,  486. 

Eudyalite,  Eudi'alyte,  275. 
Eudnpphite,  322. 
Eukairite,  v.  Eucairite. 
Eulysyte,  453. 
Eulytite,  Eulytine,  278. 
Euosmite,  349. 
Eu'photide,  487. 
Euphyllite,  335. 
Eupyr'chroite,  233. 
Euralite,  340. 
Euryte,  474. 
Eusynchite,  168.. 
Eux'enite,  222. 
Evansite,  219. 
Evigtokite,  216. 

Fahlerz,  150. 
Fahlunite,  336. 
Fairfieldite,  209. 
Famatinite,  149. 
FarOelite,  320. 
Fassa'ite,  266. 
Fau'jasite,  322. 
Fa'yalite,  277. 
Feather  ore,  164. 
Feldspar  Group,  296. 
Felsite,  302. 

Felspar,  v.  Feldspar,  296. 
Felsyte,  474. 
Ferberite,  200. 
Fergusonite,  221. 
Ferrotelluride,  193. 
Fibroferrite,  200. 
Fibrolite,  307;  456. 
Fichtelite,  348. 
Fillowite,  210. 
Fiorite,  261. 


504 


GENERAL  INDEX. 


Fioryte,  469. 

Fireblende  =  Pyrostilpnite. 

Fire-marble,  431. 

Fischerite,  219. 

Fleches  d'amour,  180,  258. 

Flint,  256,  469. 

Float-stone,  201. 

Flos  ferri,  238. 

Pluel'lite,  216. 

Fluidal  texture,  444. 

Fluocerine,  221. 

Fluocerite,  221. 

Fluor,  Fluorite,  227. 

Fluor  spar,  227. 

Fluorides,  Aluminium,  216. 

Calcium,  227. 
Folliated  tellurium,  164. 
Fontainebleau  limestone,  236. 
Foresite,  325. 
Forsterite,  277. 
Fowlerite,  268. 
Foyayte,  479. 
Franklandite,  231. 
Franklinite,  197. 
Fredericite,  149. 
Free-stone,  Brown-stone,  462. 
Frei'bergite,  150. 
Frei'esleb'enite,  133. 
French  chalk,  326,  490. 
Fren'zelite,  114. 
Freyalite,  318. 
Frie'delite,  278. 
Frieseite,  131. 
Frigidite,  150. 

Gabbro,  484,  487. 
Gadol'inite,  284. 
Gagates,  352. 
Gah'nite,  214. 
Gale'na,  Gale'nite,  160. 
Galenobismutite,  164. 
Galmei,  174. 
Ganomalite,  169. 
Garnet,  278;  449,  455. 

rock,  487. 
Garnetyte,  487. 
Garnierite,  185. 
Gas,  Natural.  342. 
Gastal'dite,  273. 
Gay-Lussite,  249. 
Gearksutite,  216. 
Qednnite,  349. 
Gehlenite,  306. 


Genth'ite,  185,  332. 

Geoc'erite,  349. 

Geoc'ronite,  164. 

Geodes,  66. 

Geomyricite,  349. 

Gerhardtite,  154. 

Gersdorffite,  183. 

Gey'serite,  261,  469. 

Gibbsite,  213. 

Gie'seckite,  293,  334,  474. 

Gigan'toiite,  335,  336. 

Gillingite,  338. 

Girasol,  260. 

Gismon'dite,  Gismondine,  318. 

Glagerite,  335. 

Glaserite,  ®.  Arcanite,  246. 

Glass,  441,  454,  476. 

Glauber  salt,  246. 

Glau'berite,  246. 

Glau'codot  =  Cobaltic     Arseno 

pyrite. 

Glau'colite,  293. 
Glau'conite,  329;  464. 
Glau'cophane,  273. 
Glaucophanyte,  489. 
Globulites,  442, 
Gme'linite,  323. 
Gneiss  (pron.  like  nice),  471. 
Gold,  122. 
Gos'larite,  172. 
Gothite,  199. 
Goyazite,  219. 
Grahamite,  349. 
Gramenite,  329. 
Grammatite,  270. 
Granite,  470. 

mica-less,  471. 
Granityte,  470. 
Granular  quartz,  468. 
Granulyte,  471. 
Graphic  granite,  471. 

tellurium,  132;  129. 
Graphite,  119. 
Grastite,  340. 
Gray  antimony,  112. 

copper,  150. 

Gray-wacke,  Grau-wacke,  463. 
Green  sand,  464. 
Greenockite,  175. 
Greenovite,  312. 
Greenstone,  481,  482. 
Greisen,  472. 
Grindstones,  463. 


GENERAL  INDEX. 


505 


Grit,  462. 
Grochauite,  341. 
Groddeckite,  323. 
Groppite,  335. 
Grossularite,  279. 
Grothite,  v.  Titanite,  312. 
Grunauite,  183. 
Guadalcazarite,  143. 
Guanajuatite,  114. 
Guano,  233. 
Guariuite,  313. 
Guayac'anite,  149. 
Gueja'rite,  149. 
Gui'terman'ite,  164. 
Giimberlite,  335. 
Gum  mite,  187. 
Gurho'fite,  239. 
Guyaquillite,  349. 
Gymnite,  332. 
Gypsum,  229. 
Gyrolite,  315. 

Hai'dingerite,  234. 
Hair-salt,  224. 
Ha'lite,  243. 
Hal'lite,  339. 
Halloy'site,  335. 
Halotrichite,  200,  217. 
Hamartite  =  Bastuasite,  223. 
Hanksite,  249. 
Hannayite,  250. 
Harmotome,  323. 
Harringtonite,  321. 
Har'risite,  147. 
Hartite,  348. 

Hatch 'ettite,  Hatcbettine,  347. 
Hatchet'tolite,  187. 
Hauerite,  206. 
Haughtonite,  291. 
Hausman'nite,  207. 
Hauyne,  294. 
Hauynite,  294. 
Hauyn'ophyre,  480. 
Haydenite,  323. 
Hayesine,  232. 
Heavy  spar,  240. 
He'bronite,  218. 
Hed'enber'gite.  267. 
Hed'ypbane,  167. 
Heldburgite,  282. 
He'liotrope,  257. 
Helmintbe,  340. 
Helvite,  Helvin,  278. 


Hemafibrite,  210. 
Hem'atite,  193. 

Brown,  198. 

Red,  193. 
Hemidioryte,  480. 
Hemithrene,  482. 
Henwoodite,  220. 
Hercynite,  215. 
Herderite,  234. 
Herrengrundite,  153. 
Herschelite,  323. 
Hessite,  131. 
Hetserolite,  207. 
Heterogenite,  184. 
Heter'osite,  209. 
Heubacliite,  184. 
Heu'landite,  325. 
Hid'deuite,  269. 
Hieratite,  262. 
Hisingerite,  338. 
Hoernesite,  226. 
Hofman'nite,  349. 
Homilite,  312. 
Honey-stone,  220. 
Hopeite,  172. 
Hornblende,  270;  442,  451,  456. 

schist,  446,  488. 
Hornblende-granite,  477. 
Hornblende-picryte,  489. 
Horublendyte,  488. 
Horn  quicksilver,  143. 

silver,  134. 
Hornstone,  256,  469. 
Horse-flesh  ore,  149. 
Horton'olite,  277. 
Houghite,  213. 
Howlite,  232. 
Huantajayite,  244. 
Huascolite,  171. 
Hiib'nerite,  200. 
Hudsonite,  267. 
Hullite,  338. 
Humboldtilite,  283. 
Humboldtine,  204. 
Humboldtite,  311. 
Humite,  303,  304.. 
Huntilite,  132. 
Hureaulite,  209. 
Hyacinth,  281,  306. 
Hyalite,  261. 
Hyalomelan,  485. 
Hyalomicte,  472. 
Hyal'ophaue,  299. 


506 


GENERAL  INDEX. 


Hyalosid'erite,  277. 
Hyalotecite,  169. 
Hydrar'gillite,  213. 
Hydraulic  limestone,  236,  459. 
Hydrobo'racite,  232. 
Hydrocarbons,  342,  344,  348. 
Hydrocastorite,  270. 
Hydrocerussite,  169. 
Hydrochloric  acid,  251. 
Hydrocy'anite,  153. 
Hydrodol'omite,  239. 
Hydrofluorite,  251. 
Hydrofranklinite,  172. 
Hy'drogen,  251. 
Hy'drogio'bertite,  226. 
Hydromag'nesite,  224,  226. 
Hy'dro-mi'ca  Group,  335. 
Hydrorai'ca  schist,  473. 
Hydroneph'elite,  321. 
Hydrophane,  260. 
Hydroph'ilite,  229. 
Hydrophite,  332. 
Hydro-rho'donite,  268. 
Hydrotalcite,  213. 
Hydrozincite,  173. 
Hygroph'ilite,  290. 
Hypersthene,  264;  456. 
Hypersthene-andesyte,  484. 
Hypersthene-dioryte,  482. 
Hypersthene-gabbro,  484. 
Hypersthenyte,  484. 
Hy'peryte,  484. 
Hystatite  =  Menaccanite. 

Ib'erite,  335,  336. 

Ice,  crystallization  of,  4,  251. 

Iceland  spar,  235. 

Ice  Stone,  216. 

1'docrase,  282. 

Id'rialine,  Idrialite,  348. 

IglestrSmite,  224,  277. 

Ihleite,  200. 

Ilesite,  208. 

Il'menite,  195. 

Il'vaite,  285. 

Indianite,  298. 

Indic'olite,  305* 

Infusorial  earth,  261,  465. 

I'odar'gyrite,  134. 

Iodide,  Mercury,  144. 

Silver,  134. 
lodobromite,  134. 
lod'yrite,  134. 


I'olite,  287. 

Hydrous,  287,  336. 
lo'nite,  349. 
Ir'idos'mine,  141. 
Iron,  Ores  of,  188. 

Magnetic,  196. 

Native,  189. 

pyrites,  189. 

sinter,  203. 

Titanic,  195. 
Ironstone,  Clay,  194. 
I'serine  =  Menaccanite,  195. 
Isocla'site,  154. 
Itab'yrite,  473. 
Itacol'umyte,  468. 
Itt'nerite,  294. 
Ix'olyte,  348. 

Jacobsite,  197. 
Ja^e,  271. 
Jadeite,  271. 
Jalpaite,  131. 
Jamesonite,  164. 
Jargon,  281. 
Jar'osite,  200. 
Jasper,  257. 

rock,  469. 

Jaspery  clay  iron-stone,  194. 
Jefferisile,  339. 
Jeffersonite,  267. 
Jelletite,  279. 
Jenkinsite,  332. 
Jenzschite,  262. 
Jeremejefflte,  218. 
Jet,  352. 
Johannite,  188. 
Jollyte,  338. 
Joseite,  114. 

(K:  for  some  words  \vith  an 

initial  K,  see  under  0.) 
Kainite,  225. 
Kainosite,  318. 
Kalinite,  217. 
Kaluszite  =  Syngenite. 
Kammererite,  339. 
Kaneite,  206. 

Kaolin,  Kaolinite,  332;  464. 
Karyinite,  167. 
Keatingine,  268. 
Keilhauite,  313. 
Kentrolite,  169. 
Ker'mesite,  113. 


GENERAL  INDEX. 


507 


Kerrite,  339. 

Kersanton,  Kersantyte,  480. 
Kieserite,  225. 
Killi'nite,  334. 
Kjerulfine,  226. 
Kneb'elite,  277. 
Ko'bellite,  164. 
Ko'chelite,  221. 
Kongsbergite,  130. 
Konigite,  Konigine,  153. 
Ko'ninckite,  203. 
Konlite,  348. 
Koppite,  221. 
Kotsclmbeite,  340. 
Kottigite,  172;  184. 
Krantzite,  349. 
Kreittonite,  215. 
Krem'ersite,  193. 
Krennerite,  129. 
Krisu'vigite,  153. 
Kronkite,  153. 
Kru'gite,  225. 
Kupfferite,  273. 
Ky'anite,  308;  457. 

Lab'radi'oryte,  482. 
Labradorite,  298;  442,  457. 
Labradorite-dioryte,  482. 
Lag'onite,  200. 
Lampadite,  208. 
Lan'arkite,  166. 
Langite,  153. 
Lanthanite,  223. 
Lanthanum  ores,  221. 
Lapis-lazuli,  295. 
Lapis  ollaris,  326. 
Larderellite,  250. 
Laumontite,  Lauraonite,  315. 
Laurite,  141. 
Lautite,  149. 
Lawreucite,  193. 
Laz'ulite,  218. 
Lead,  Ores  of,  160. 
Leadhillite,  166. 
Lecont'ite,  250. 
Ledererite,  323. 
Led'erite,  313. 
Lebrbachite,  164. 
Lehuntite  =  Natrolite,  321. 
Leidyite,  317. 
Lennilite,  302. 
Lenz'inite,  335. 
Leonhardite,  316. 


Lepidok'rokite,  199. 
Lepid'olite,  289. 
Lepidom'elane,  291. 
Leptinyte,  v.  Granulyte. 
Lettsomite  =  Cyanotricbite,  153. 
Leucbtenbergite,  340. 
Leucite,  295 ;  455. 
Leucite  Rocks,  479. 
Leuco-tepbrite,  480. 
Leucitopbyre,  479. 
Leucityte,  480. 
Leucochalcite,  154. 
Leucomanganite,  209. 
Leucotile,  319. 
Leucoph'anite,  277. 
Leucopyrite,  193. 
Leu'coxene,  312,  453. 
Levyne,  Levynite,  323. 
Lber'zolyte,  488. 
Libetb'enite,  154. 
Lie'bigite,  188. 
Lie'vrite  =  Ilvaite,  285. 
Lignite,  351. 
Lillite,  338. 
Limbachite.  332. 
Limburgyte,  488. 
Limestone,  235,  457,  460. 

Hydraulic,  459. 
Limnite,  199. 
Li'monite,  198. 
Linarite,  166. 
Lindackerite,  185. 
Linnse'ite,  181. 
Lionite,  108. 
Lip'aryte,  476. 
Liroco'nite,  153. 
Liskeardite,  220. 
Listwianyte,  489. 
Litbioph'ilite,  209. 
Lithioph'orite,  207. 
Litbograpbic  stone,  459. 
Lith'omarge,  335. 
Liver  ore,  143. 
Livingstonite,  113. 
Lodestone,  197. 
Loess,  Loss,  465. 
Lo'ganite,  339. 
Lol'lingite,  193. 
Lopboite,  340. 
Lovenite,  282. 
Loweite,  225. 
LSwigite,  217. 
Lox'oclase,  301. 


508  ' 


GEtfEKAL  INDEX. 


Luckite,  200. 
Ludlamite,  203. 
Ludwigite,  225. 
Lumachelle,  459. 
Lilneburgite,  226. 
Luzonite,  v.  Enargite. 
Lydian  stone,  Lydite,  257. 
Lyncurium,  306. 

Mac'le,  305. 

Macfarlanite,  132. 

Maconite,  339. 

Magneferrite,  224. 

Magnesite,  226. 

Magnesium,  Compounds  of,  223. 

Magnetic  iron  ore,  196. 

pyrites,  192. 
Mag'netite,  196;  31,  455. 
Magnoferrite,  204. 
Mag'uolite,  144. 
Mal'achite,  Blue,  156. 

Green,  154. 
Malac'olite,  266. 
Mal'acon,  282. 
Maldonite,  123. 
Malinowskite,  150. 
Mallar'dite,  208. 
Manganblende,  206. 
*Manganbrucite,  224. 
Manganepidote  =  Piedmontite, 

284. 

Manganese  ores,  206. 
Manganese  spar,  268. 
Manganhedenbergite,  267. 
Man'ganite,  207. 
Manganosite,  206. 
Manganostibite,  206. 
Mangantantalite,  202. 
Marble,  235,  459,  460. 
Mar'casite,  191. 
Marekanite,  ®.  Pearlyte. 
Mar'garite,  341. 
Margar'odite,  290,  335. 
Margarophyllite  Section,  326. 
Mar'ialite,  293. 
Marl,  460. 

Marmatite  =  ferriferous  Blende. 
Mar'molite,  330. 
Marsh  gas,  342. 
Martite,  194. 

Mascagnite,  Mascagnine,  250. 
Masonite,  341. 
Matlockite,  165. 


Matricite,  318. 
Maxite,  166. 
Medjidite,  188. 
Meer'schaum,  323. 
Mei'onite,  293. 
Melac'onite,  151. 
Mel'anite,  279. 
Melanocliroite,  166. 
Melan'olite,  338. 
Melanophlo'gite,  262. 
Melanosiderite,  199. 
Melanotecite,  169. 
Melanothal'lite,  151. 
Melan'terite,  199. 
Mel'aphyre,  483,  485. 
Mel'ilite,  Mel'lilite,  283. 
Melilite-basalt,  486. 
Meliph'anite,  Melin'ophane,  277. 
Mellite,  220. 
Me'lonite,  183. 
Menac'canite,  195;  455. 
Men'dipite,  165. 
Mendo'zite,  217. 
Meneghi'nite,  164. 
Menilite,  261. 
Mercury,  Ores  of,  142. 
Meroxene,  291,  457. 
Mes'itine,  Mes'itite,  204. 
Mesole,  820. 
Mesolite,  321. 
Mes'otype  =  Natrolite. 
Melabrushite,  234. 
Metachlorite,  319. 
Metacinnabarite,  143. 
Metax'ite,  330. 
Metaxoite,  338. 
Meymacite,  109. 
Miar'gyrite,  133. 
Miar'olyte,  470. 
Mias'cyte,  479. 
Mica,  Mica  Group,  287;  457. 

hydrous,  335. 
Mica-dioryte,  480,  482. 
Mica-porphyrite,  480. 
Mica  schist,  473. 
Mica-trachyte,  475. 
Michaelsonite,  284. 
Mic'rocline,  300. 
Microgranite,  470. 
Micropegmatite,  471. 
Mic'rolite,  234;  222. 
Microlites,  441. 
Mic'rosom'mite,  294. 


GENERAL  INDEX. 


509 


Middletonite,  349. 
Milarite,  273. 
Millerite,  181. 
Millstone  grit,  426, 
Mim'etene,  Mimetite,  167. 
Mineral  coal,  350. 

oil,  344. 

pitch,  349. 
Minette,  473. 
Minium,  165. 
Mirab'ilite,  246. 
Mise'nite,  246. 
Mispickel,  192. 
Mixite,  154. 
Mizzonite,  293. 
Mocha  stone,  256. 
Molybdate,  Lead,  166. 
Molyb'denite,  108. 
Molybdite  =  yellow  oxide,  109. 
Molybdomenite,  168. 
Molysite,  193. 
Mon'azite,  222. 
Monetite,  234. 
Moniraolite,  168. 
Monite,  234. 
Mon'radite,  317. 
Mon'tanite,  "114. 
Montebrasite,  218. 
Mon'ticel'lite,  277. 
Montmartite,  v.  Gypsum. 
Montmorillonite,  329. 
Moonstone,  299,  301. 
Mordenite,  326. 
Morenosite,  185. 
Moronolite  =  Jarosite,  200. 
Mor'venite,  324. 
Mosaic  gold,  178. 
Mosan'drite,  285. 
Moss  agate,  256. 
Mottrammite,  168;  154. 
Mountain  cork,  271. 

leather,  271. 

tallow,  347. 
Muller's  glass,  261. 
Mundic,  191. 
Muriatic  acid,  251. 
Muromontite,  284. 
Muscovite,  288. 
Muscovy  glass,  289. 

Nadorite,  168. 
Nagyagite,  164;  129. 
Naphtha,  345. 


Naphthalin,  348. 
Nat'rolite,  321. 
Natron,  249. 
Nauman'nite,  131. 
Nec'rouite,  302. 
Needle  ore,  164. 
Nefdauskite,  141. 
Neft-gil,  347. 
Ne'malite,  223. 
Ne'ochry'solite,  277. 
Neocianite,  157. 
Neot'ocite,  338. 
Nepheline-doleryte,  486. 
Nepheline-tephryte,  486. 
Neph'elinyte,  486. 
Neph'elite,  Nepheline,  293;  455. 
Nephelite  rocks,  478,  486. 
Neph'rite,  271. 
Neudorfite,  349. 
Nevadite,  476. 
Newberyite,  226. 
Nic'colite,  182. 
Nickel-gymnite,  332. 
Nickel,  Ores  of,  180. 

stibine,  183. 

vitriol,  185. 
Ni'grine,  179. 
Niobite  =  Columbite,  201. 
Niobium,  Compounds  of,  201. 
Nitrate,  Calcium,  234. 

Potassium,  247. 

Sodium,  248. 
Nitratine,  248. 
Nitre,  247. 
Nitrobarite,  242. 
Nitrocalcite,  234. 
Nitromagnesite,  226. 
No'cerine,  224. 
Nohlite,  221. 
Nontronite,  329. 
Noryte,  484. 
Nosean,  Nosite,  294. 
Noumeite,  185. 
No  vac' uly  te,  468. 
Nut'talite,  293. 

Obsidian,  476;  442. 
Ochre,  Brown,  198. 

Red,  194. 

Yellow,  198. 
Octahe'drite,  180. 
(Ellach'erite,  290. 
GErstedite,  282. 


510 


GENERAL  INDEX. 


Ogcoite,  340. 

O'kenite,  315. 

Oil.  Mineral,  344. 

Oktib'behite,  189. 

Olafite  =  Albite. 

Ol'igoclase,  299;  457. 

Oliv'enite,  153. 

Ol'ivine,  277;  456;  v.  Chrysolite. 

Olivine-gabbro,  484. 

Omphacite,  487. 

Ouofrite,  143. 

Onta'riolite,  293. 

Onyx,  256. 

Oolite,  236. 

Opal,  259;  454. 

Opal  Jasper,  261. 

O'phicalce,  490. 

O'phiolite,  330. 

Ophiolyte,  490. 

O'pbyte,  482. 

Or'angite,  318. 

Orileyite,  193. 

Or'piment,  111. 

Or'thite,  284. 

Orth'oclase,  300;  442,  456. 

Ortholyte,  473. 

Oryzite,  326. 

Osteolite,  233. 

Ot'trelite,  341. 

Ouvar'ovite,  280. 

Ozar'kite,  320. 

Ozoc'erite,  Ozokerite,  347. 

Pach'nolite,  216. 
Packfong,  186. 
Pago'dite,  335. 
Palag'onite,  335. 
Palatinite,  485. 
Palla'dium,  141. 
Pandermite,  231. 
Paraffin,  347. 
Paragonite,  290. 

schist,  474. 
Parank'erite,  239. 
Paran thine,  293. 
Parastil'bite,  326. 
Par'gasite,  272. 
Parisite,  223. 
Par'ophite,  335. 
Parophite  schist,  473. 
Partzite,  154. 
Pattersonite,  341. 
Paulite  =  Hypersthene,  264. 


Pealite,  v.  Geyserite. 
Pearl  sinter,  261,  469. 
Pearl  spar,  239. 
Pearlstoue,  Pearlyte,  442,  476. 
Peat,  352. 
Peck'hamite,  278. 
Pectolite,  315. 
Peganite,  219. 
Pegmatolite,  «.  Orthoclase. 
Pegmatyte,  470,  471. 
Pelagite,  207. 
Pelhamite,  331. 
Pencil-stone,  328. 
Pennine,  Penninite,  339. 
Pennite,  239. 
Peperino,  464. 
Per'iclase,  Periclasite,  223. 
Peridot,  277. 
Peridotyte,  489. 
Perof  skite,  Perowskit,  180. 
Pet'alite,  269. 
Petro'leum,  344. 
Petrosi'lex,  474. 
Petrified  wood,  258. 
Petuntze,  334. 
Petzite,  132;  129. 
Phac'olite,  323. 
Pharmac'olite,  234. 
Phar'macosid'erite,  203. 
Phen'acite,  275. 
Phengite,  289. 
Philadelphite,  339. 
Philippite,  153. 
Phillipsite,  324. 
Phlog'opite,  290. 
Phoanicochroite,  166. 
Phol'erite,  335. 
Phon'olyte,  479. 
Phos'genite,  169. 
Phosphate,  Aluminium,  218. 

Ammonium,  250. 

Calcium,  232,  234. 

Cerium,  222. 

Copper,  153. 

Iron,  202. 

Lead,  167. 

Manganese,  208. 

Uranium,  187. 

Yttrium,  222. 
Phos'phoce'rite,  223. 
Phosphochalcite,  154. 
Phosphochro'mite,  168. 
Phosphorite,  233. 


GENERAL  INDEX. 


511 


Phosphuranylite,  188. 
Phthanyte,  469. 
Phyllite,  341. 
Phyllyte,  463. 
Physalite,  309. 
Phytocollite,  349. 
Picite,  203. 
Pick'eringite,  217. 
Pic'otite,  214. 
Picrallumogen,  218. 
Picroepidote,  284. 
Pic'rolite,  330. 
Picrom'erite,  225. 
Pic'rophyll,  317. 
Pic'rosmine,  317. 
Pic'ryte,  488. 
Piedmou'tite,  284. 
Pilarite,  157. 
Pilinite,  318. 
Pilolite,  317. 
Plmelite,  185. 
Pinguite,  329. 
Pi'nite,  334;  474. 
Pi'nitoid,  335. 
Pinnoite,  225. 
Pinolite  ==  Magnesite. 
Pipe-clay,  464. 
Pisanite,  200. 
Pi'solite,  236. 
Pis'tacite,  284. 
Pitchblende,  186. 
Pitchstone,  476;  442. 
Pitkarandite,  317. 
Pitticite  =  Iron  Sinter,  203. 
Plagiocitrite,  217. 
Plag'ioclase,  296. 
Plag'ionite,  164. 
Plasma,  257. 
Plaster  of  Paris,  230. 
Plal'iniridium,  141. 
Plat'inum,  Native,  139. 
Ple'onaste,  214. 
Plessite  =  Gersdorffite,  183. 
Plumba'go,  119. 
Plumbic  ochre,  165. 
Plumbogummite,  165. 
Plumbostan'nite,  164. 
Polianite  =  Pyrolusite,  206. 
Polishing  powder,  466. 
Pol'lucite,   275. 
Pollux,  275. 
Pol'yar'gite,  335. 
Pol'yar'gyrite,  133. 


Polyar'senite,  210. 
Pol'ybasite,  133;  149. 
Pol'ycrase,  222. 
Polyd'ymite,  181. 
Pol'yhal'ite,  225. 
Polylite,  267. 
Polylith'ionite,  290. 
Pol'ymig'nite,  222. 
Porcelain  jasper,  475. 
Porcel'anyte,  475. 
Porcel'lophite,  330. 
Porfido  verde  antico,  452. 
Por'pezite,  142. 
Por'phyrite,  481. 
Porphyritic  structure,  440. 
Porphyroid,  472. 
Por'phyry,  440,  474. 

Antique  green,  440,  485. 

Antique  red,  440,  481. 

Felsyte,  474. 

Globular,  474. 
Portland  cement,  461. 
Portor,  458. 

Potassium,  Compounds  of,  243. 
Potstone,  326. 
Potter's  clay,  464. 
Poz'zuola'na,  464. 
Prase,  255.  • 
Pregrat'tite,  290. 
Prehn'ite,  317. 
Priceite,  231. 
Prochlorite,  340. 
Proid'onite,  262. 
Propylyte,  483. 
Prosepnite,  347. 
Pros'opite,  216. 
Protobastite  v.  Bronzite,  264. 
Protogine,  472. 
Protovermiculite,  339. 
Proustite,  133. 
Przi'bramite,  175. 
Psammite  v.  Sandstone. 
Pseudobrookite,  180. 
Pseudomalachite,  154. 
Pseudonatrolite,  321. 
Pseud'ophite,  339. 
Pseudosmaragdite,  274. 
Pseudotriplite,  209. 
Psilom'elane,  207. 
Psittac'inite,  169;  154. 
Pterolite,  v.  Lepidomelane. 
Pucherite,  114. 
Pudding-granite,  470. 


512 


GENERAL  INDEX. 


Pudding-stone,  462. 

Pum'ice,  476. 

Purple  copper  =  Bornite,  148. 

Pycnite,  309. 

Pyral'lolite,  317;  327. 

Pyrar'gillite,  336. 

Pyrar'gyrite,  132. 

Pyrene'ite,  279. 

Py'rite,  189;  5,  6,  30,  455. 

Pyri'tes,  Arsenical,  192. 

Auriferous,  190. 

Capillary,  181. 

Cobalt,  181. 

Cockscomb,  191. 

Copper,  147,  148. 

Hepatic,  191. 

Iron,  189. 

Magnetic,  192. 

Radiated,  191. 

Spear,  191. 

White  iron;  191. 
Py'roau'rite,  224. 
Py'rochlore,  234;  222. 
Py'rochro'ite,  207. 
Py'rolu'site,  206. 
Pyromeride,  474. 
Py'romor'phite,  167. 
Py'rope,  279. 
Py'rophos'phorite,  234. 
Py'rophyl'lite,  828. 

slate,  490. 

Py'rophyl'lyte,  490. 
Py'rophy'salite,  309. 
Py'roscle'rite,  338. 
Pyros'malite,  318. 
Pyrostibite  =  Kermesite,  113. 
Py'rostilp'nite,  134. 
Py'roxene,  265;  453,  456. 
Pyrox'enyte,  488. 
Pyr'rhosid'erite,  199. 
Pyr'rhotite,  192. 

Quartz,   253;   55,   56,  442,   451, 

455. 

Granular,  468. 
Quartzyte,  468. 
Quartz-dioryte,  481. 
Quartz-porphyry,  470,  471,  472, 

474,  476,  483,  485. 
Quartz-trachyte,  476. 
Quartz-syenyte,  477. 
Quicklime,  235. 
Quicksilver,  142. 


Rai'mondite,  200. 
Ralstonite,  216. 
Randite,  188. 
Rath'olite,  315. 
Rau'ite,  335. 
Realgar,  111. 
Red  antimony,  113. 

chalk,  194. 

copper  ore,  151. 

hematite,  194. 

lead,  165. 

ochre,  194. 

silver  ore  132,  133. 

zinc  ore,  171. 
Reddingite,  209. 
Redruth'ite,  146. 
Refdanskite,  330. 
Reichardtite,  224. 
Reinite,  201. 
Reissite,  326. 
Rem'ingtonite,  185. 
Rens'selaerite,  326,  490. 
Restor'melite,  335. 
Retin'alite,  330. 
Retinite,  476. 
Retzbanyite,  164. 
Rhab'dophane,  223. 
Rhse'tizite,  309. 
Rhagite,  114. 
Rhodium  gold,  123. 
Rho'dizite,  225. 
Rho'dochrome,  339. 
Rho'dochro'site,  210. 
Rho'donite,  268. 
Rho'dophyl'lite,  339. 
Rhomb-spar,  239. 
Rhy'olyte,  476. 
Rich  ell  ite,  203. 
Rinkite,  285. 
Ripid'olite,  340. 

Ritting'erite,  near  Freieslebenite. 
Riv'otite,  154. 
Rock  cork,  271. 

crystal,  254. 

gas,  342. 

meal,  236. 

milk,  236. 

oil,  344. 
.     salt,  243. 

tallow,  347. 
Roep'perite,  277. 
Rces'slerite,  226. 
Rogersite,  222. 


GENERAL  INDEX. 


513 


Romeine,  Romeite,  234. 

Roscoelite,  336. 

Roselite,  184. 

Rosite,  335. 

Rosso  antico,  440. 

Rosterite,  274. 

Rothoffite,  279. 

Rottisite,  185;  332. 

Ru'bellite,  305. 

Rubislite,  340. 

Ruby,  Oriental,  212. 

Ruby  silver,  Ruby-blende,  132, 133. 

Ruby,  Spinel,  214. 

Ruin  marble,  459. 

Rutlie'nium,  Ores  of,  141. 

Ru'therfordite,  223. 

Ru'tile,  179;  59. 

Safflorite,  182. 
Sag'enite,  179. 
Sahlite,  266. 
Sal  ammoniac,  249. 
Salmiak,  249. 
Salt,  Common,  243;  31. 
Samarskite,  221. 
Sandbergerite,  149. 
Sand-rock,  463. 
Sandstone,  462. 
San'idin,  301. 
Sap'onite,  332;  329. 
Sapphire,  211. 
Sar'colite,  293. 
Sard,  256. 
Sardou'yx,  256. 
Sar'kinite,  210. 
Sartorite,  164. 
Sas'solite,  Sas'solin,  109. 
Satin-spar,  229,  235. 
Saus'surite,  285;  410,  449. 
Savite,  v.  Natrolite. 
Scap'olite,  292;  455. 
Scar'broite,  319. 
Scheelite,  232. 
Schiller-spar,  331;  450. 
Schirmerite,  134. 
Schneebergite,  234. 
Schorl  (pron.  Short),  305. 
Sdiorl'omite,  314. 
Schorl-rock,  488. 
Schraufite,  349. 
Schrei'bersite,  192. 
Schrockeringite,  188. 
Schr5tterite,  318. 


Schwatzite,  150. 
Scleret'inite,  349. 
Scolecite,  Scolezite,  321. 
Scor'odite,  203. 
Scotiolite,  338. 
Sco'villite,  223. 
Scythe-stone,  463. 
Selenide,  Lead,  164. 

Mercury,  143. 

Silver,  131,  132. 
Selenite,  229. 
Selenite,  Copper,  154. 

Lead,  168. 
Selenpal'ladite,  142. 
Sel'laite,  223. 
Semseyite,  164. 
Semiopal,  260. 
Sen'armont'ite,  113. 
Serpierite,  153. 
Se'piolite,  328. 
Ser'icite,  290,  335. 

schist,  473. 
Ser'pentine,  329;  490. 
Sev'erite,  335. 
Sey'bertite,  342. 
Shale,  463. 
Siderazote,  193. 
Sid'erite,  203. 
Sideromelan,  486. 
Sid'erona'trite,  200. 
Sid'erophyl'lite,  291. 
Siegburgite,  349. 
Sie'genite,  181. 
Silaonite,  114. 
Silex  =  Quartz,  253. 
Silfbergite,  273. 
Sil'ica,  90,  253,  259. 
Silicate,  Copper,  157. 

Lead,  169. 

Manganese,  268. 

Nickel,  185. 

Zinc,  173,  174. 
Siliceous  sinter,  261,  469. 

slate,  469. 

Silicified  wood,  258. 
Silicoborocalcite,  232. 
Sillimanite,  305. 
Silt,  465. 
Silver,  129. 

compounds  of,  129. 

glance,  129. 

Silver-lead  ore,  135,  161. 
Sinter,  Iron,  203. 


514 


GENERAL  INDEX. 


Sinter,  Siliceous,  261. 
Simonyite,  225. 
Sipylite,  222. 
Sis'inondine,  341. 
Sisserskite,  141. 
Skolopsite.  294. 
SkutterudUe,  183. 
Slags,  443. 
Slate,  463. 

Smaltite,  SmaHine,  181. 
Smectite,  328. 
Smithsonite^  172. 
Snow,  crystals  of,  4. 
Soapstone,  326,  489. 
Soda-granite,  480. 
Soda  nitre,  248. 
So'dalite,  294. 

Sodium,  Compounds  of,  243. 
Sommarugaite,  183. 
Som'mite,  293. 
Sonomaite,  217. 
Spathic  iron,  203. 
Spath'iopy'rite,  183. 
Spear  pyrites,  191. 
Speckstein  =  Steatite,  326. 
Specular  iron,  194. 
Specular  schist,  473, 
Speculum  metal,  109. 
Spelter,  174. 

solder,  159, 
Spessartite,  279. 
Sphserosiderite,  204. 
Sphal'erite,  170. 
Sphene,  312. 
Spherocobaltite,  185. 
Spherulites,  445,  455,  476. 
Spilite,  485. 
Spinel',  213. 
Spinthere,  v.  Titanite. 
Sphe'rostil'bite,  325. 
Spod'iosite,  234. 
Spod'umene,  269. 
Stalac'tite,  236. 
Stalag'mite,  236. 
Stannite,  176. 

Staurolite,  Staurotide,  313;  456. 
Stear'gillite,  329. 
Steatargillite,  340. 
Ste'atite,  326. 
Steatyte,  489. 
Steeleite,  326. 
Steph'anite,  133. 
Stercorite,  250, 


Sterlingite,  290. 
Sternbergite,  131. 
Stetefeldite,  154. 
Stibnite,  112. 
Stilbite,  324. 
Stilpnom'elane,  329. 
Stinkstone,  237. 
Stolpenite,  329. 
Stolzite,  166. 
Strakonitzite,  317. 
Strat'ope'ite,  338. 
Strengite,  203. 
Strigovite,  338. 
Stromey'erite,  131. 
Strontianite,  242. 
Strontium,  Compounds  of,  240, 
Stru'vite,  250. 
Stu'belite,  338. 
Stiltzite,  132. 
Sty'loty'pite,  149. 
Succinite,  279,  349. 
Succinuin,  349. 
Sulphatallophane,  318. 
Sulphate,  Aluminium,  216. 

Ammonium,  250. 

Barium,  240. 

Calcium,  229,  230. 
'   Cobalt,  184. 

Copper,  152. 

Iron,  199. 

Lead,  165. 

Magnesium,  224. 

Nickel,  184. 

Potassium,  246. 

Sodium,  246. 

Strontium,  242. 

Uranium,  188. 

Zinc,  172. 
Sulphide,  Antimony,  112. 

Arsenic,  111. 

Bismuth,  114. 

Cadmium,  175. 

Cobalt,  181. 

Copper,  147,  148. 

Iron,  189,  192. 

Lead,  130. 

Manganese,  206. 

Mercury,  143. 

Molybdenum,  108. 

Nickel,  181. 

Ruthenium,  141. 

Silver,  131. 

Tin,  176. 


GENERAL   INDEX. 


515 


Sulphide,  Zinc,  170. 
Sulphur,  Native,  106;  38. 
Sulphuret,  see  Sulphide. 
Sulphuric  acid,  107. 
Sulphurous  acid,  107. 
Sunstone,  299,  301. 
Susan'nite,  166. 
Sus'sexite,  226. 
Sy'enyte,  477. 
Syenyte  gneiss,  477. 

Quartz,  477. 
Syl'vauite,  132. 
Sylvine,  Sylvite,  243. 
Synadelphite,  210. 
Syn'genite,  246. 
Szaboite,  264. 
Szaibelyte.  225. 
Szmikite,  208. 

Tab'asheer,  261. 
Tabular  spar,  265. 
Tachhy'drite,  224. 
Tach'yaphal'tite,  282. 
Tach'ylyte,  485. 
Tsenite,  189. 
Tagilite,  154. 
Talc,  326. 
Talcose  schist,  489. 
Talctriplite,  209. 
Tantalite,  202. 
Tapalpite,  132. 
Ta'rapa'caite,  246. 
Tasmanite,  349. 
Taznite,  114. 
Telluride,  Bismuth,  114. 

Gold,  129,  132. 

Lead,  164. 

Mercury,  143. 

Silver,  131,  132. 
Tellurite,  108. 
Tellurium,  Bismuthic,  102. 

Foliated,  164. 

Graphic,  132. 

Native,  108. 
Tellurous  acid,  108. 
Teng'erite,  223. 
Ten'nantite,  149. 
Ten'orite,  151. 
Teph'roite,  277. 
Teph'ryte,  480,  486. 
Tere'nite,  335. 
Teschemacherite,  250. 
Teschenyte,  486. 


Tetrad'ymite,  114. 
Tetrahe'drite,  150;  121. 
Thau'masite,  239. 
Thenard'ite,  246. 
Thermona' trite,  249. 
Thin'olite,  236. 
Thomsen'olite,  216. 
Thomsonite,  320. 
Thorite,  318. 
Thraulite,  338. 
Throm'bolite,  154. 
Tlmlite,  285. 
Thu'mite,  286. 
Thurin'gite,  341. 
Tiemannite,  143. 
Tile  Ore,  151. 
Till,  465. 
Tin,  Native,  176. 
Tin  ore,  Tin  stone,  176. 
Tin  pyrites,  176. 
Tincal'conite,  247. 
Tinkal,  246. 
Titanic  iron,  195. 
Titanite,  312. 
Titanium,  Ores  of,  178. 
Titanomor'phite,  312. 
Thinolite,  236. 
Tiza,  «.  Ulexite,  231. 
Tocornalite,  134. 
Tonalyte,  481. 
Topaz,  309. 

False,  255. 

Oriental,  212. 
Topaz'olite,  279. 
Tobermorite,  315. 
Tor'banite,  349,  352. 
Torbernite,  187. 
Touchstone,  257. 
Tour'maline,  304;  455. 
Tourmalyte,  488. 
Trach'ydol'eryte,  483. 
Trach'yte,  475;  442. 
Tract'olyte,  450. 
Trap,  481,  485. 
Trav'ersellite,  317. 
Trav'ertine,  236,  460. 
Trem'olite,  270. 
Tri'chites,  442. 
Tric'lasite,  336. 
Trid'ymite,  262;  443,  455. 
Tripestone,  231. 
Triph'ylite,  Triphyline,  208. 
Trip'lite,  209. 


516 


GENERAL  1KDEX. 


Triploidite,  209. 
Trip'olite,  261,  465. 
Tripolyte,  465. 
Trippkeite,  154. 
Tritochorite,  168. 
Trit'omite,  318. 
Troctolyte,  486. 
Tro'gerite,  188. 
Troilite,  192. 
Trona,  249. 
Troostite,  173. 
Tscheffkinite,  313. 
Tschermakite,  v.  Oligoclase. 
Tschermigite,  217,  250. 
Tufa,  Tuff,  463. 
Tufa,  Calcareous,  236. 
Tungstate,  Copper,  152. 

Iron,  200. 

Lead,  166. 

Lime,  232. 
Tungstic  ochre,  109. 
Tungstite,  109. 
Turgite,  199. 
Turnerite,  222. 
Turquois,  219. 
Tutenague,  186. 
Tyr'olite,  154. 
Tysonite,  221. 

Uin'tahite,  349. 
Ulexite,  231. 
Ullman'nite,  183. 
Ul'tramarine,  295. 
Unakyte,  478. 
Unghwarite,  329. 
Unionite,  v.  Zoisite. 
Uraconise,  Uraconite,  188. 
U'ralite,  268,  451. 
TJranin,  Uraninite,  186. 
U'ranite,  187. 
Uranium,  Ores  of,  186. 
Uranmica,  187. 
U'ranochal'cite,  188. 
U'ranocir'cite,  188. 
Uranopilite,  188. 
Uranospinite,  188. 
Uranotan'talite  =  Samarskite. 
U'ranothallite,  188. 
Uranothorite,  188,  318. 
Uranotil,  188. 
Uranvitriol,  188. 
Urpethite,  347. 
Vrusite,  200. 


Urvolgyite,  153. 
U'tahite,  200. 

Valentinite,  113. 
Vanadate,  Copper,  154. 

Lead,  168. 
Vanad'inite,  168. 
Var'iolyte,  487. 
Varis'cite,  219. 
Vasite,  284. 
Yauque'linite,  166. 
Velvet  copper  ore,  153. 
Venasquite,  337. 
Ven'erite,  341. 
Venice  white,  241. 
Verd- antique,  330,  461,  490. 

Oriental  440. 

Verde  di  Corsica  duro,  487. 
Vermic'ulite,  338. 
Vermilion,  143. 
Vesu'viauite,  282. 
Veszelyte,  154. 
Viandite,  261. 
Vietinghofite,  221. 
Villar'site,  318. 
Vir'idite,  337. 
Vitreous  copper,  146. 

silver  =  Argentite,  181. 
Vitriol,  Blue  or  Copper,  152. 

Green  or  Iron,  199. 

White  or  Zinc,  172. 
Vitrophyre,  476. 
Viv'ianite,  202. 
Vogliauite,  188. 
Voglite,  188. 
Voigtite,  336. 
Volborthite,  154. 
Volcanic  glass,  476. 
Volknerite,  213. 
Vol'taite,  200. 
Voltzite,  172. 
Vorhau'serite,  330. 
Vul'pinite,  231. 

Wacke,  464. 
Wad,  207. 
Wagnerite,  226. 
Walchowite,  349. 
Walkerite,  315. 
Walpurgite,  188. 
Waltherite,  114. 
Waluewite,  342. 
Warringtonite,  v.  Brochantite. 


GENERAL  INDEX. 


517 


Warwickite,  225. 
Washingtonite,  195. 
Water,  251 ;  4. 
Watte villite,  246. 
Wa'vellite,  220. 
Websterite,  218. 
Wehrlite,  114. 
Weiss-stein,  471. 
Wer'nerite,  292. 
Werthemanite,  218. 
Westanite,  v.  Fibrolite. 
Wheel-ore.  149. 
Whetstone,  468. 
Whewellite,  239. 
White  arsenic,  111. 

lead  ore,  168. 
Whitneyite,  149. 
Wichtine,  Wichtisite,  273. 
Willcoxite,  341. 
Wil'lemite,  173;  278. 
Williamsite,  330. 
Wilsonite,  335. 
Winkworthite,  v.  Howlite. 
Witherite,  241. 
Wittichenite,  149,  150. 
Wittingite,  338. 
Wohlerite,  278. 
Wolfram,  Wolframite,  200. 
Woll'astonite,  265. 
Woll'ongong'ite,  349. 
Wood-opal,  261. 
Wood'wardite,    near     Cyanotri- 

chite. 

Wulf  enite,  166. 
Wurtzite,  171. 

Xantho'conite,  149. 
Xanthophyllite,  342. 


Xanthosiderite,  199. 
Xen'otime,  222. 
Xyl'otine,  317. 

Ye'nite,  285. 
Youngite,  171. 
Ytter-garnet,  279. 
Yttrium  ores,  221. 
Yttrocerite,  221. 
Yttrotantalite,  221. 
Yttrotitanite,  313. 

Zaffre,  185. 
Zar'atite,  185. 
Zeag'onite,  318. 
Zeolite  Section,  319. 
Zephar'ovichite,  220. 
Zeunerite,  188. 
Zietrisikite,  347. 
Zinc,  ores  of,  170. 

blende,  170. 

bloom,  173. 

Native,  170. 
Zinc-aluminite,  172. 
Zincite,  171. 
Zink'enite,  164. 
Zinn'waldite,  290. 
Zipp'eite,  188. 
Zircon,  281 ;  455. 
Zir'conite,  281. 
Zircon-syenyte,  478. 
Zirlite,  213. 
Z5b'litzite,  332. 
Zoi'site,  285;  456. 
Zonochlorite,  317. 
Zorgite,  164. 
Zunyite,  314. 
Zwieselite,  v.  Triplite. 


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